THE  RECESSION  OF  THE  LAST 

ICE  SHEET  IN  NEW  ENGLAND 

ERNST  ANTEVS 

AMERICAN  GEOGRAPHICAL  SOCIETY 

RESEARCH  SERIES  NO.  1 1 


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THE  CATHERINE^  O^mm^  bfflF\Ry 


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LAST  ICE  RECESSION  IN 
NEW  ENGLAND 


AMERICAN  GEOGRAPHICAL  SOCIETY 

RESEARCH  SERIES  NO.   II 

W.  L.  G.  Jo  ERG  J  Editor 

THE  RECESSION  OF  THE  LAST  ICE 
SHEET  IN  NEW  ENGLAND 

BY 

ERNST  ANTEVS 

University  of  Stockholm 

WITH  A  PREFACE  AND  CONTRIBUTIONS 

BY 
J.  W.  GOLDTHWAIT 


AMERICAN  GEOGRAPHICAL  SOCIETY 

BROADWAY  AT  I56TH  STREET 

NEW   YORK 

1922 


THE  CATHERINE 


WESTON 


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LIBRARY 


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COPYRIGHT,    1922 

BY 

THE  AMERICAN  GEOGRAPHICAL  SOCIETY 

OF  NEW  YORK 


THE  aiHERINrBKO'CONNdR  LIBRARY 

WESTON  OBLATORY 

WESTON  ^,^SSAGMJSETTS 


JUL  0  8  1988 


THE   CONDE    NAST   PRESS 
GREENWICH,   CONN. 


BQSnM  COUEK  UBMinr 

CHBINUT  mi.  «M  02167 


CONTENTS 

CHAPTER  PAGE 

.  Preface,  by  J.  W.  Goldthwait vii 

Introduction xi 

I  Varve  Clay,  and  the  Method  of  Investigation        i 

II  Conditions  in  New  England  During  the  Deposi- 

tion OF  the  Varve  Clay      7 

III  Description  of  the  Sections  at  the  Localities 

Studied ii 

IV  The  Normal  Curve      47 

V  The  Connections     64 

VI  Abnormal  Varves,  and  Disturbances  in  the  Clay      69 

VII  The  Rate  of  Recession  and  Conditions  Con- 
trolling Recession      74 

VIII  The  Climate  During  the  Recession,  and  Cli- 
matic Periodicity 89 

IX  The  Bearing  of  These  Studies  on  Previous  Work 

AND  ON  New  Problems 94 

Explanation  of  the  Map  Illustrating  the  Re- 
cession OF  THE  Last  Ice  Sheet  from  New  Eng- 

LAND  AND  NeW  YoRK,  BY  J.  W.  GOLDTHWAIT    .     .       I04 

List  of  References   io8 

Index 117 


LIST  OF  ILLUSTRATIONS 

FIG.  PAGE 

1  Manner  of  deposition  of  varve  clay 2 

2  An  exposure  of  varve  clay facing  4 

3  View   showing  the   method   of   measuring   the   clay 

layers facing  5 

4  Sample  of  measurement  made  in  the  field  and  curve 

constructed  from  it  in  the  office 5 

5-12  Maps  showing  the  position  of  the  localities  examined 

in  the  Connecticut  Valley.   Scale,  1:160,000    .    .    .      37-44 

13  Map  showing  the  position  of  the  localities  examined 

in  the  Merrimac  Valley.   Scale,  1:160,000    ....  45 

14  Curves  showing  three  drainages  of  ice-ponded  lakes 

into  the  Connecticut  River  above  the  Passumpsic  71 

15  Section  at  locality  24,  southeast  of  Amherst,  Mass.     .  77 

16  Part  of  curves  at  localities  19  and  20,  Northampton, 

Mass 78 

17  Annual  rate  of  ice  retreat  in  southern  Finland,  after 

Sauramo 92 

18  Curve    showing    drainage    during    years    5671-5676 

recorded  at  locality  a,  Catskill,  N.  Y 98 

19  Part  of  curves  at  localities  27  and  28  near  Greenfield, 

Mass 102 

Plates 
Pl. 

I-V  [Normal  curve,  covering  4,400  years  in  21  sections, 
recording  the  recession  of  the  edge  of  the  last  ice  sheet 
from  Hartford,  Conn.,  to  St.  Johnsbury,  Vt.  (At  bot- 
tom of  PI.  V,  curves  I-III,  three  groups  of  individual 
curves  illustrating  connections  and  correspondences 
within  each  group)] At  end 

VI  Map  Illustrating  the  Recession  of  the  Last  Ice  Sheet 
from  New  England  and  New  York,  compiled  by  J.  W. 
Goldthwait.  Scale,  i:  1,250,000 At  end 


PREFACE 

Dr.  Antevs'  study  of  the  recession  of  the  last  ice  sheet  from 
New  England  is  something  new  and  significant.  It  differs  so 
much,  indeed,  in  method  from  previous  studies  by  glacialists  in 
America,  and  the  range  of  its  applications  is  so  wide,  that  no 
brief  introduction  can  quite  do  it  justice.  Fortunately,  these 
methods  are  so  simple  that  they  are  readily  understood  and  put 
to  practice.  As  for  the  broad  application  of  such  work  as  this 
to  solving  problems  of  glacial  history  and  climate  and  the  accom- 
panying migrations  of  plants  and  animals  and  of  primitive  man, 
an  attentive  reader  may  form  his  own  judgment. 

Ever  since  Louis  Agassiz  conceived  the  idea  of  former  con- 
tinental ice  sheets  over  northern  Europe  and  North  America, 
geologists  of  the  two  continents  have  been  gathering  evidences 
of  them.  New  England,  the  home  of  Agassiz  almost  from  the 
time  when  his  glacial  theory  was  announced  until  his  death, 
presents  varied  and  plentiful  proof  of  glaciation.  The  grooves 
and  striae  on  the  rocks,  the  southward  dispersion  of  stones  and 
boulders,  and  the  varieties  of  "drift"  deposits  had  already  been 
observed  and  speculated  upon  by  Edward  Hitchcock,  W.  W. 
Mather,  C.  T.  Jackson,  and  other  pioneers  in  New  England  and 
New  York  when  Louis  Agassiz  advanced  his  theory  of  an  ice 
sheet.  Although  they  recognized  the  fact  that  the  puzzling 
"drift  phenomena"  corresponded  to  records  made  by  living 
glaciers,  American  geologists  for  twenty  or  thirty  years  hesitated 
to  accept  the  new  explanation,  owing  to  the  difficulty  of  con- 
ceiving of  a  glacier  so  thick  and  so  extensive  that  it  could  spread 
its  records  continuously  across  uplands  and  valleys.  The 
unhappy  effect  of  an  inhospitable  attitude  toward  a  new  theory 
and  new  methods  was  clearly  illustrated  here  during  the  period 
from  1841  to  1870,  when  the  "glacial  theory"  was  on  probation. 
Lively  discussions  of  it,  as  reported  in  contemporary  proceedings 
of  our  scientific  societies,  betray  the  human  tendency  to  judge 


viii  ICE  RECESSION  IN  NEW  ENGLAND 

a  theory  by  the  number  and  prestige  of  its  adherents  and  converts 
instead  of  by  careful  and  impartial  consideration  of  the  evidence. 
This  experience,  already  forgotten  in  the  subsequent  development 
of  a  complete  demonstration  of  the  truth  of  Agassiz'  theory, 
should  keep  us  from  committing  a  similar  mistake  in  our  attitude 
toward  this  new  and  surprising  work  of  Dr.  Antevs. 

Whatever  advance  in  science  comes  from  such  studies  as  this 
must  be  accredited  in  the  first  place  to  the  genius  of  Baron 
Gerard  De  Geer  of  Stockholm.  His  discovery  of  a  simple, 
graphic  way  to  correlate  layers  of  clay  at  one  locality  with  the 
layers  at  another  locality,  and  thus  to  identify  them  as  the 
record  of  the  same  years,  is  the  starting  point  for  the  new  proc- 
esses of  study.  In  Europe  the  development  of  the  new  methods 
by  De  Geer  and  his  associates,  Liden,  Carlzon-Caldenius, 
Sandegren,  Antevs,  Sauramo,  and  others,  has  already  indicated 
the  possibility  (a)  of  determining  an  exact  time  scale  of  late 
glacial  and  post-glacial  time,  (b)  of  reconstructing  the  position 
of  the  ice  border  more  or  less  accurately  during  each  year  of  its 
withdrawal,  (c)  of  measuring  the  rate  of  its  recession,  in  meters 
per  year,  (d)  of  detecting  halts  or  zones  of  retarded  recession 
even  where  these  are  not  registered  by  recessional  moraines, 
(e)  of  working  out  the  complicated  changes  of  drainage  that 
took  place  as  ponded  waters  were  released  and  modern  river 
systems  inaugurated,  and  even  (f)  of  computing  with  accuracy 
the  rate  of  regional  uplift  of  the  region  during  the  departure  of 
the  ice  sheet.  In  short,  De  Geer  and  his  colleagues  have  made 
great  progress  in  the  working  out  of  a  detailed  history  of  the 
retirement  of  the  border  of  the  last  land  ice  from  northern 
Europe,  of  the  evolution  of  climate,  and  of  the  migrations  of 
plants,  animals,  and  primitive  man.  The  literature  of  these 
studies  is  but  little  known  in  America;  and  the  few  reviews  and 
abstracts  covering  them  suffer  from  lack  of  a  first-hand  knowledge 
of  unpublished  studies  such  as  that  which  Dr.  Antevs  possesses 
and  uses  in  this  memoir  to  good  advantage.  It  will  be  noticed 
that  he  sees  limitations  as  well  as  wonderful  possibilities  in  the 
methods  inaugurated  by  De  Geer. 


PREFACE  ix 

The  student  of  glacial  history,  particularly  in  New  England 
and  New  York,  will  discover  in  this  study  an  amazing  array  of 
conclusions.  Dr.  Antevs  has  traced  a  series  of  clay  layers  which 
mark  approximately  4,000  successive  years  up  the  Connecticut 
Valley  from  Hartford,  Conn.,  to  St.  Johnsbury,  Vt.  He  has  found 
large  parts  of  the  same  series  duplicated  in  the  Hudson  and  Merri- 
mac  Valleys.  He  has  worked  out  successive  positions  of  the  reced- 
ing ice  border,  after  only  a  few  months  of  field  work,  in  a  region 
where  two  generations  of  American  geologists,  baffled  by  the  ab- 
sence of  definite  moraines,  have  realized  little  or  no  success.  The 
estimate  of  time  occupied  by  this  recession  is  a  simple  arithmetical 
count,  expressed  not  in  centuries  but  in  years.  Such  accuracy 
can  never  be  claimed  for  our  computations  of  time  from  the 
Niagara  gorge,  where  large  factors  are  only  imperfectly  measur- 
able. An  investigation  so  precise  in  method  and  execution  and 
so  suggestive  will  give  fresh  impulse  to  our  studies  of  Pleistocene 
glaciation.  There  is  scarcely  a  problem  of  the  history  of  this 
curious  and  interesting  period  that  Dr.  Antevs'  work  does  not 
touch.  It  suggests,  for  instance,  where  we  should  look  for  reces- 
sional moraines  and  how  moraines  at  widely  separated  points 
should  be  correlated.  It  stimulates  more  thorough  study  of  the 
records  made  in  flooded  valleys  and  ponded  lakes,  with  their 
shifting  complicated  outlines,  and  of  the  upward  and  downward 
warpings  of  the  region  which  accompanied  the  withdrawal  of 
the  ice  sheet.  It  assigns  to  each  deposit  its  proper  date,  which, 
while  not  as  yet  connected  with  later  records  so  as  to  permit  it  to 
be  expressed  as  so  many  years  "B.C.,"  is  nevertheless  as  accurately 
referred  to  a  certain  point  in  the  glacial  period  as  dates  of  human 
history  are  referred  to  the  beginning  of  the  Christian  era. 

The  larger  number  of  readers,  who  are  not  specialists  in  geology 
but  who  are  interested  in  the  measurement  of  time,  in  prehistoric 
climate,  and  in  the  migrations  of  plants  and  animals,  will  see  in 
these  geochronological  studies  a  key  which,  if  properly  used  in 
other  regions,  may  settle,  better  than  any  other  means  yet 
found,  the  question  whether  ice  sheets  on  different  continents 
were  contemporaneous  or  not.     The  attitude  of   Dr.   Antevs 


X  ICE  RECESSION  IN  NEW  ENGLAND 

toward  that  end  is  hopeful  yet  cautious.  He  sees  the  solution  in 
a  thorough  reconstruction  of  a  standard  line  of  observations  in 
each  place,  through  which  to  measure  and  identify  the  long 
periods  of  climatic  change. 

The  attention  which  Dr.  Antevs  has  given  in  the  field  to  the 
collecting  of  additional  material  to  check  up  his  correlations  and 
the  care  with  which  he  has  measured  his  sections,  plotted  his 
curves,  compared,  corrected,  and  finally  combined  these  curves 
so  as  to  work  out  one  "normal  series"  to  express  continuous 
climatic  variations  of  more  than  4,000  years  will  be  apparent  to 
anyone  who  examines  his  data.  His  patient  scientific  treatment 
of  the  problem  will  be  fully  appreciated,  however,  by  those 
who  put  these  methods  to  practice  and  make  measurements 
and  graphs  of  their  own.  It  is  a  kind  of  study  that  will  be  most 
illuminating  as  it  comes  to  be  associated  with  other  methods 
already  in  use. 

J.  W.  GOLDTHWAIT 

Dartmouth  College, 
Hanover,  N.  H. 


INTRODUCTION 

In  all  history  a  knowledge  of  exact  time  is  vital.  Chronology 
is  the  thread  on  which  events  are  tied  like  pearls  on  a  string. 

The  history  of  the  earth  was  a  history  without  absolute 
time,  without  dates,  until  Gerard  De  Geer,  forty  years  ago,  found 
a  way  which  enabled  him  and  Ragnar  Liden  to  work  out  a 
chronology  of  the  last  13,500  years.  De  Geer's  and  Liden's 
time  scale  has  the  year  as  its  unit,  and  is  exact.  It  is  based  on 
annual  layers  in  clay  and  silt,  varves,^  very  much  resembling 
annual  rings  of  trees.  The  clay  was  deposited  in  lakes  in  front 
of  the  receding  edge  of  the  ice  sheet,  and  in  fiords  in  northern 
Sweden  after  the  ice  had  disappeared.  Except  for  the  last  few 
hundred  years,  this  time  scale  comprises  the  whole  time  since 
the  land  ice  uncovered  southernmost  Sweden.  The  retreat  of  the 
ice  from  southern  Sweden  to  Ragunda,  270  miles  north-northwest 
of  Stockholm,  took  about  5,000  years;  and  the  time  that  has 
elapsed  since  then  is  found  by  Liden  to  be  about  8,500  years. 
Accordingly,  the  uncovering  of  southernmost  Sweden  began 
about  13,500  years  ago. 

During  192 1  the  writer,  who  had  come  to  America  as  a  member 
of  Baron  De  Geer's  party  in  1920,  began  to  work  out  a  chron- 
ology of  North  America  in  late  glacial  time^  and  to  that 
end  studied  the  recession  of  the  last  ice  sheet  in  New  England 
and  New  York  State.  The  present  paper  is  based  upon  field 
work  carried  on  during  five  and   a   half  months  and   chiefly 

1  "The  Swedish  word  varv,  subst.  (old  spelling:  hvarf),  means  as  well  a  circle  as 
a  periodical  iteration  of  layers.  An  international  term  for  the  last  sense  being 
wanted,  it  seems  suitable  to  use  the  transcription  varve,  pi.  -s.,  in  English  and 
French,  while  in  German  it  might  be  written  Warw,  pi.  -e"  (De  Geer,  1912,  p.  253; 
1912a,  p.  458;  for  publications  cited  see  List  of  References  at  the  end  of  the 
volume). 

2  Post-glacial  time,  according  to  the  Swedish  chronology,  begins  the  year  after 
the  bisection  of  the  shrinking  ice  sheet  at  Ragunda  in  northern  Sweden.  The  term 
"late  glacial"  refers  to  the  time  occupied  by  the  recession  of  the  last  land  ice  up 
to  the  event  mentioned.  Accordingly,  in  this  paper  the  time  occupied  by  the  ice 
retreat  in  New  England  will  be  called  late  glacial. 


xii  ICE  RECESSION  IN  NEW  ENGLAND 

comprises  investigations  in  the  Connecticut  Valley  from  Hart- 
ford, Conn.,  to  St.  Johnsbury,  Vt.,  and  in  the  Merrimac  Valley 
around  Concord,  N.  H.  Field  work  lasting  two  months  was 
carried  on  during  the  same  season  in  the  Hudson  and  Champlain 
Valleys  and  north  of  St.  Johnsbury,  but  little  use  is  made  here 
of  the  material  collected  outside  New  England.  While  a  chro- 
nology of  the  ice  retreat  from  Hartford  to  St.  Johnsbury  has 
been  obtained,  this  is  not  connected  with  present  time;  and  so 
the  question.  How  long  ago?  cannot  be  answered. 

No  time  and  trouble  have  been  spared  to  make  the  normal 
curve,  which  has  been  compiled  from  the  original  measurements, 
as  accurate  as  possible  with  respect  to  both  number  and  thickness 
of  the  varves  so  that  it  may  form  a  reliable  framework  for  future 
detailed  studies.  It  is  in  the  extraordinary  possibilities  of  the 
geochronological  studies  for  accuracy  and  for  detail,  as  well  as 
in  their  wide  bearing  not  only  on  geology  but  also  on  other 
fields  of  science,  particularly  geography,  climatology,  and 
archeology,  that  their  scientific  value  and  great  importance  are 
to  be  found. 

The  field  work  was  carried  out  on  a  scholarship  from  the 
Sverige  Amerika  Stift"elsen  in  Stockholm  and  a  special  grant 
from  the  National  Research  Council  in  Washington,  and  with 
private  means. 

The  successful  completion  of  this  field  work  and  the  working 
up  of  this  memoir  are  principally  due  to  the  kind  interest  of 
Professor  J.  W.  Gold th wait  of  Dartmouth  College;  Professor 
Edward  B.  Mathews  of  Johns  Hopkins  University;  Mr.  Robert 
W.  Sayles,  curator  of  the  Geological  Museum  of  Harvard 
University;  and  the  American  Geographical  Society  of  New 
York.  Professor  Goldthwait  has  ever  since  our  first  meeting 
aided  me  in  word  and  deed.  He  has  participated  in  the  field 
work,  and  he  has  compiled  the  map  (PI.  VI),  which  has  made  it 
possible  to  correlate  the  history  of  New  England  with  that  of 
the  Great  Lakes.  During  the  writing  of  the  memoir,  at  Dart- 
mouth, his  advice  and  help  have  been  of  the  greatest  value. 
He  has  also  bestowed  much  labor  on  its  form.  Professor  Mathews, 


INTRODUCTION  xiii 

as  chairman  of  the  Division  of  Geology  and  Geography  of  the 
National  Research  Council,  has  done  much  to  raise  funds  for 
the  field  work  and  to  interest  geological  surveys  in  the  northern 
states.  Mr.  Sayles  has  kindly  supported  the  preparation  and 
printing  of  the  illustrations.  The  American  Geographical 
Society  put  me  in  a  position  to  work  up  my  material  into  this 
form  and  has  attended  to  its  publication. 


CHAPTER  I 


VARVRCLAY,  AND  THE  METHOD  OF 
^  ^';— -^  j^YES-p  jQ^  J  JON 


Formation  of  Varve  Clay 

In  the  glaciated  areas  most  of  the  soils  were  formed  during 
the  disappearance  of  the  last  ice  sheets.  Part  of  the  water  from 
the  melting  glacier,  working  down  through  fissures  in  the  ice, 
sought  its  way  down  to  the  ground.  Here  it  formed  a  river  and 
dug  a  tunnel  in  the  lower  part  of  the  ice.  Under  hydrostatic 
pressure  and  with  tremendous  velocity  the  river  rushed  toward 
the  ice  edge,  carrying  with  it  big  boulders,  stones,  gravel,  sand, 
and  mud.  When  it  reached  the  ice  border  the  pressure  gave  out, 
and  the  transporting  power  was  reduced  to  a  trifle.  Boulders 
and  gravel,  consequently,  were  unloaded  at  the  mouth  of  the 
tunnel  and  just  beyond  it,  forming  eskers  and  outwash.  The 
annual  deposition  of  coarse  material  was  often  very  considerable. 
If  the  glacial  river  discharged  into  standing  water,  coarse  sand 
was  deposited  in  the  direction  of  the  current  for  some  hundred 
yards  from  the  ice  edge,  while  silt  could  be  transported  consider- 
able distances  and  fine  clay  carried  more  than  fifty  miles. ^ 

In  North  America  large  areas  which  now  form  fertile  clay 
lands  were  covered  by  water  at  the  disappearance  of  the  ice. 


1  I  mile  =  S,28o  feet  =  1.6093  kilometers. 
I  yard  =  3  feet  =  0.915  meter. 
I  foot  =  12  inches  =  30.48  centimeters. 
I  inch  =  2.54  centimeters. 


I  kilometer  =  0.6214  mile. 

I  meter  =  i.i  yard  =  3.28  feet  = 

39-37  inches. 
I  centimeter  =  0.3937  inch. 


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ICE  RECESSION  IN  NEW  ENGLAND 


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Fig.  I — Figure  showing  manner  of  deposition  of  varve  clay  in  fresh  water  off 
the  receding  ice  front  during  three  successive  years. 

Some  lowlands  were  covered,  because  the  land  stood  lower  than 
it  does  today,  and  others  were  occupied  by  lakes  which  were 
ponded  by  the  ice  or  by  a  different  inclination  of  the  land.  If 
the  glacial  river  flowed  into  fresh  or  slightly  salt  water,  the 
cold  melting  water  followed  the  bottom  on  account  of  its  high 
specific  gravity.    The  silt  and  part  of  the  clay  dropped  to  the 


METHOD  OF  INVESTIGATION  3 

bottom  rather  soon,  but  for  the  most  part  the  finest  particles 
remained  suspended-  for  a  long  time,  and  settled  during  the 
late  fall  and  winter.  Consequently,  at  first  silt  and  coarse  clay, 
then  finer  and  finer  clay,  were  deposited  on  the  lake  bottom 
during  a  year.  The  silty  part,  however,  contains  a  considerable 
quantity  of  rather  fine  particles,  which  evidently  were  pulled 
down  by  those  of  greater  size  (Oden,  1920,  p.  339).^  Accordingly, 
the  sediments  of  the  year  became  clearly  separated  from  those 
of  the  preceding  year.  These  annual  layers  are  the  layers  called 
varves.  Clays  derived  from  fine-grained  slates  or  deposited 
during  a  time  of  very  little  melting  and  slow  current,  however, 
are  sometimes  practically  homogeneous,  because  even  those 
parts  deposited  during  the  summer  are  greasy.^ 

If,  on  the  contrary,  the  glacial  river  discharged  into  salt  or 
strongly  brackish  water,  as  was  the  case  on  the  Swedish  west 
coast  and  on  the  Atlantic  coast  north  of  Boston,  the  ice  water 
rose  to  the  surface  because  of  its  lower  specific  gravity.  On 
account  of  the  salinity  even  the  finest  material  settled  rather 
soon;  and  on  the  sea  bottom  a  more  or  less  homogeneous  clay 
was  deposited,  a  clay  in  which  large  grains  are  mixed  with  the 
very  finest.    It  follows  that  marine  clays  show  no  varves. 

Method  of  Investigation 

That  the  distinct  period  of  time  recorded  by  each  layer  is  the 
year  was  suggested,  as  it  seems  independently,  by  several 
American  and  Swedish  geologists,  by  Alfred  Smith  in  1832 
(p.  229),  Edward  Hitchcock  in  1841  (p.  359),  De  Geer  in  1882, 
Emerson  in  1887  (p.  404),  Upham  in  1888  (p.  132),  and  Taylor 

2  Publications  are  cited  tiius  throughout  this  work.  For  full  titles  see  List  of 
References  at  the  end  of  the  volume. 

'  Deposition  of  glacial  varve  clay  evidently  ceased  when  the  land  ice  had  dis- 
appeared. In  the  fiords  in  northern  Sweden,  however,  deposition  of  another  kind 
of  annually  laminated  clay  followed.  This  clay,  on  which  the  post-glacial  chronology 
is  based,  is  silty  and  very  thinly  laminated  and  shows  only  faint  difference  between 
the  two  zones  which  mark  the  year.  The  upper  dark  gray  zone,  the  equivalent  of 
the  winter  layer  in  the  glacial  varve  clay,  is  essentially  deposited  in  connection 
with  the  flood  of  the  rivers  during  the  melting  of  the  snow  in  spring  (Liden.  191 1, 
P-  273). 


4  ICE  RECESSION  IN  NEW  ENGLAND 

in  1894  (p.  288).  All  of  them  used  this  peculiarity  as  a  means 
for  determining  the  time  occupied  by  the  formation  of  certain 
clay  deposits,  but  De  Geer  (1884,  1885)  alone  went  farther  and 
found  a  way  to  make  it  the  basis  for  a  chronology  of  the  closing 
stage  of  the  Ice  Age.   His  method  is  the  following. 

Since  the  varves  were  deposited  in  front  of  the  receding  ice 
edge,  they  cover  each  other  like  shingles  on  a  roof  (Fig.  i). 
Since,  also,  their  thickness  varied  from  year  to  year  and  stood 
in  direct  relation  to  the  amount  of  annual  melting,  which  in 
its  turn  was  chiefly  determined  by  the  summer  temperature 
(see  p.  85),  it  is  possible  to  recognize  the  varves  from  widely 
separated  localities,  provided  they  lie  within  a  climatologically 
uniform  area.  Furthermore,  it  is  possible  to  determine  the 
rate  of  the  retreat  of  the  ice.  To  this  end  exposures  in  clay 
pits,  bluffs,  or  special  excavations  (Fig.  2)  are  smoothed  with 
spade  and  brick  trowel,  and  the  series  of  varves  are  measured 
from  the  bottom,  if  possible,  by  marking  the  varve  limits  care- 
fully on  narrow  strips  of  strong  paper  (Fig.  3).  The  field  measure- 
ments are  transformed  into  curves  or  graphs  on  paper  ruled  with 
lines  spaced  exactly  five  millimeters  apart,  since  experience  has 
proved  that  to  be  the  best.  The  thickness  of  the  lowest  varve 
is  set  off  on  the  first  vertical  line,  the  second  varve  on  the  next 
line  to  the  right  of  the  former,  and  so  on,  and  the  points  marking 
the  thickness  of  the  varves  are  connected  (Fig.  4)."*  The  graph 
thus  secured  is  compared  with  one  from  another  locality  by 
moving  the  two  until  they  match,  which,  as  already  explained, 
they  do  if  they  have  a  series  of  varves  in  common.  If  the  bottom 
varve  at  one  locality  is  found  to  correspond  to  varve  number 
37  at  a  more  southerly  locality,  the  ice  border  evidently 
withdrew  over  this  place  36  years  earlier  than  over  the  former 
place. 

If  the  varves  are  very  thin  or  for  some  other  reason  difficult 

*  De  Geer,  in  order  to  emphasize  the  stratigraphy,  originally  plotted  the  varves 
on  a  series  of  horizontal  lines,  beginning  with  the  lowest  line  and  measuring  in 
from  the  left  edge  of  the  paper.  When  it  proved  inconvenient  to  compare  the 
graphs  in  that  position,  he  turned  them  90°  but  kept  the  sequence  of  the  varves; 
so  that  on  his  graphs  the  first  or  lowest  varve  is  to  the  right. 


Fig.  3 — View  showing  the  method  of  measuring  the  clay  layers  on  a  strip  of  paper. 
Locality  67,  Hanover,  N.  H. 


METHOD  OF  INVESTIGATION 


\A^^AA/\A/ 


(3) 


(2) 


(I) 


:&^ 


to  measure  in  the  field,  it  is  advisable  to 
take  a  series  of  samples  to  measure  at  home. 
Samples  of  different  types  of  clay  also  make 
valuable  material  for  museum  exhibit  and 
teaching.  The  samples  are  taken  in  tight 
troughs  of  zinc  plate,  50  centimeters  long,  5 
centimeters  wide,  and  2  centimeters  high. 
The  face  of  the  clay  bank  is  carefully 
smoothed,  and  the  trough  is  cautiously 
pressed  in,  a  knife  being  used  to  cut  away 
the  clay  just  outside  the  edges,  until  the 
trough  is  entirely  filled.  The  samples  are 
taken  so  that  they  overlap  each  other  5 
centimeters.  The  troughs  are  then  cut  loose 
from  the  bank,  and  part  of  the  clay  which 
projects  above  the  edges  is  removed.  If 
moistened  and  wrapped  in  wax  paper,  such 
samples  keep  in  good  condition  for  months. 
In  the  laboratory  the  clay  is  carefully  cut 


Fig.  4 — Sample  of  measurement  made  in  the  field  and  curve  constructed  from 
it  in  the  office.    Actual  scale. 


6  ICE  RECESSION  IN  NEW  ENGLAND 

down  to  the  edges  of  the  trough.  If  the  clay  has  dried,  it  must  be 
gradually  moistened  and  brought  back  to  its  natural  consistency 
before  it  is  cut.  It  is  then  treated  with  glycerine  as  fast  as  the 
water  evaporates.  When  all  the  water  is  replaced  the  clay 
retains  its  natural  appearance  unchanged. 


CHAPTER  II 

CONDITIONS  IN  NEW  ENGLAND  DURING  THE 
DEPOSITION  OF  THE  VARVE  CLAY 

Higher  Elevation  of  Southern  New  England  in  Late 

Glacial  Time 

While  the  last  ice  sheet  was  disappearing,  southern  New 
England  had  a  higher  position  than  now.  This  is  proved  by  the 
occurrence  of  excellent  varve  clays  at  New  Haven,  Conn., 
more  than  25  feet  below  sea  level,  and  at  Hackensack,  N.  J., 
down  to  more  than  15  feet.  The  clays  were  deposited  in  entirely 
fresh  water,  in  lakes,  not  in  bays  of  the  sea.  Varve  clays,  to  be 
sure,  were  formed  in  the  sea  close  to  the  mouth  of  a  glacial  river; 
but,  as  the  ice  edge  retired  from  the  place  and  the  amount  of 
melting  water  diluting  the  sea  water  grew  less,  homogeneous 
clays  were  deposited.  Varve  clays  also  were  deposited  in  long 
bays  where  the  water  was  brackish.  In  both  cases,  however,  the 
varves  were  indistinct,  differing  considerably  from  those  de- 
posited in  fresh  water.  These  facts,  as  already  explained,  are 
well  known  from  studies  in  Sweden.  In  the  marine  area  of 
southeastern  New  Hampshire  the  clays  are  found  to  be  homo- 
geneous. If  the  sea  had  covered  Hackensack  and  New  Haven 
in  late  glacial  time,  probably  about  ten  varves  at  the  bottom  of 
the  clays  might  have  been  distinguishable,  while  the  rest  of  the 
clay  would  have  been  homogeneous. 

Accordingly  the  terminal  moraine  south  of  New  York  City 
must  have  been  continuous  where  it  now  is  broken  between  Perth 
Amboy  and  Staten  Island  by  Arthur  Kill  and  between  Staten 
Island  and  Long  Island  by  the  Hudson,  at  the  Narrows.  Peet 
(1904,  p.  641)  and  Salisbury  (1908)  discuss  the  subject  and 
hold  forth  this  as  an  alternative.  Arthur  Kill,  near  its  southern 
end,  now  is  46  feet  deep,  and  the  Narrows  reach  a  depth  of  1 16 
feet.  Both  of  them  have  no  doubt  been  silted  up  in  post-glacial 
time. 


8  ICE  RECESSION  IN  NEW  ENGLAND 

Long  Island  Sound  a  Lake 

The  absence  of  a  bairrier  off  the  clay  marshes  at  New  Haven 
seems  to  show  that  Long  Island  Sound  in  late  glacial  time  was 
separated  from  the  sea  and  held  a  lake.  The  ponding  of  a  lake 
with  a  level  of  about  40  feet  (Dana,  1870,  p.  66)  above  present 
sea  level  at  New  Haven  evidently  signifies  that  the  threshold 
separating  the  basin  from  the  sea  stood  at  the  same  altitude. 
The  sill  at  the  present  time  between  Long  Island  and  Fisher's 
Island,  just  southwest  of  Fisher's  Island,  rises  to  within  210  feet 
of  the  surface  of  the  sea.  To  what  extent  the  original,  late 
glacial  threshold  has  been  cut  deeper  cannot  be  said,  but  50  to 
60  feet  seem  likely,  judging  from  the  chart.  The  original  sill, 
then,  should  now  lie  at  a  depth  of  about  150  feet,  and  the  level 
of  the  glacial  lake  should  incline  from  40  feet  above  sea  level 
at  New  Haven  to  about  150  feet  below  it  on  the  threshold. 
The  distance  from  New  Haven  straight  south  to  the  shore 
of  Long  Island,  which  lies  in  about  the  same  relation  to  New 
Haven  as  does  the  threshold,  is  twenty-three  miles.  The  in- 
clination under  these  conditions  should  be  about  8  feet  to  the 
mile. 

Rising  of  Peripheral  Land  Following  on  Recession 
OF  Ice,  and  Subsequent  Sinking 

At  New  Haven  the  writer  measured  200  varves  and  at  Hacken- 
sack  400,  the  measured  horizons  only  representing  parts  of  the 
clay  beds.  At  Hackensack  there  are  surely  more  than  1,000 
varves,  probably  many  more.  The  existence  of  the  barrier  of 
the  lakes  for  so  long  a  time  indicates  that  the  region,  at  the 
release  of  the  ice,  did  not  stand  in  its  highest  position  but  took 
it  when  the  ice  front  was  farther  away.  As  the  land  rose  the 
barriers  were  cut  down.  Since  little  erosion  may  have  occurred 
below  the  level  of  the  sea,  eastern  Long  Island  may  have  reached 
a  level  about  185  feet  higher  than  the  present.  The  conditions 
in  southern  New  England  were  much  the  same  as  in  the  Baltic 
region  in  late  glacial  time  (Antevs,  1922),   At  the  release  of  the 


LATE  GLACIAL  CONDITIONS  9 

ice  the  region  south  of  the  Baltic  stood  higher  than  now,  while 
Fenno-Scandia  was  submerged.  The  evidence  collected  is 
believed  to  indicate  that  the  magma  was  pressed  ouc  from  under 
the  center  of  the  ice  sheet,  causing  the  peripheral  regions  to  rise. 
As  the  ice  melted  and  the  pressure  decreased,  the  magma  regained 
its  lost  ground,  and  so  the  receding  ice  edge  was  followed  by  the 
crest  of  a  wave  of  elevation.  When  the  crest  passed  northward, 
the  peripheral  region  sank  until  equilibrium  was  regained. 
Whether  the  sinking  of  the  southern  New  England  region  was 
interrupted  by  oscillations  or  not  is  unknown. 

Physiographic  evidences  for  an  elevation  of  the  lower  Hudson 
district  in  late  glacial  time  were  presented  long  ago  by  Wood- 
worth  (1905a,  p.  229;  see  also  Barrell,  1915,  p.  15).  The  opinion, 
advanced  especially  by  Fairchild  (1914,  1919),  that  southern 
New  England  and  New  York  were  submerged  at  this  time  does 
not  seem  to  be  supported  by  any  facts. 

The  district  south  of  Boston,  when  uncovered,  seems  to  have 
had  the  same  elevation  as  now,  while  the  land  north  of  it  was 
depressed  beneath  the  sea  and  with  increasing  amount  towards 
the  northwest  (PI.  VI). 

Formation  of  Lakes  at  Ice  Front;  Their  Sediments 
THE  Records  Here  Studied 

Because  of  this  northward  inclination  of  the  land,  chains  of 
long  narrow  lakes  were  ponded  off  the  receding  ice  front.  By 
some  geologists  these  have  been  regarded  as  bays  of  the  sea. 
In  recent  years  Goldthwait  has  undertaken  to  revise  the  water 
levels  in  the  Connecticut  and  Merrimac  Valleys  by  detailed 
study.  The  exact  position  of  the  extinct  water  planes  is  not  3'et 
known,  and  so  only  the  general  outlines  of  the  lakes  after  Lough- 
lin  (1905),  Emerson  (1898),  and  C.  H.  Hitchcock  (1878)  are 
shown  in  Figures  5-13. 

Glacial  rivers  loaded  with  material  discharged  into  the  lakes, 
and  each  year  a  varve  of  clay  or  silt  was  deposited  all  over  the 
lake  bottom.    The  deposition,  if  undisturbed,  proceeded  until 


10  ICE  RECESSION  IN  NEW  ENGLAND 

the  lakes  were  filled  up  with  sediments,  which  required  a  consid- 
erable length  of  time,  since  most  of  them  were  very  deep.  The 
lake  at  Woodsville,  N.  H.,  lasted  more  than  i,6co  years,  as 
recorded  by  the  very  thin  varves  at  locality  73. 

As  northern  New  England  rose  and  the  southern  part  sank, 
and  as  the  rivers  cut  down  the  barriers  at  the  southern  ends 
of  the  lakes,  the  remnants  of  them  were  drained.  While  the 
warping  of  the  land  proceeded,  the  rivers  began  to  cut  through 
the  lake  beds  and  to  expose  the  sediments.  These  sections  of 
varve  clay  are  the  records  studied. 


CHAPTER  III 

DESCRIPTION  OF  THE  SECTIONS  AT  THE 
LOCALITIES  STUDIED 

In  the  following  a  description  is  given  of  the  sections  at  the 
localities  studied.  Their  locations  are  indicated  on  the  series  of 
maps,  as  follows:  localities  i-6,  Fig.  5;  7-25,  Fig.  6;  26-28, 
Fig.  7;  29-34,  Fig.  8;  35-43,  Fig.  9;  44-60,  Fig.  13;  61-67,  Fig-  10; 
68-73,  Fig.  11;  74-91,  Fig.  12.  The  layers  in  the  sections  are 
enumerated  from  the  top  downward. 

Localities  in  the  Connecticut  Valley 

I. — 2>/4  miles  SSW  of  Hartford  (railroad  station).  Conn., 
Charter  Oak  Park,  Park  Brickyard  on  the  eastern  side  of 
the  railroad.  Close  to  the  railroad  a  hollow  was  dug  down 
to  a  depth  of  15  feet  below  the  bottom  of  the  clay  pit. 

S  feet  weathered  varve  clay. 

Gray  brown  clay  with  thin  reddish  zones,  varves  3001-3454.^ 

Lamination  very  good.    Small  disturbance  at  about  varve 

3240. 
8  inches  slidden  zone. 
Silt  to  quicksand,   22   varves.    Average  thickness  of  varves 

2  inches. 
10  inches  slidden  zone. 
Silt  to  quicksand,  27  varves.    Average  thickness  of  varves 

iK  inches. 
Depth  to  substratum  unknown.    In  the  vicinity  the  thickness 

of  the  clay  is  by  borings  found  to  be  about  100  feet. 

Series  measured  13001-3200,  3001-3167,  3055-3346,  3115- 
3207,  3155-3206,  3171-3346,  3250-3454- 

1  For  numbering  of  the  varves  see  page  49. 


12  ICE  RECESSION  IN  NEW  ENGLAND 

2. — 300  3'ards  W  of  locality  i,  brickyard  W  of  the  railroad. 

2  feet  unlaminated  sand. 

3  feet  weathered  varve  clay. 

Gray  brown  clay  with  good  lamination. 
Depth  to  bottom  considerable. 

Series  measured:  3467-3866,  3478-3669,  3590-3781. 


3. — 1>2  miles  NNE  of  Hartford,  Windsor  Ave.  and  Kensington 
St.,  Nevel's  Brickyard. 

3-5  feet  fine,  unlaminated  sand. 

3-4  feet  clay,  often  with  wavy  varves,  deposited  in  too  shallow 

water.  Some  slidden  zones.  Not  connected  with  the  normal 

curve. 
2K-4  feet  slidden,  homogeneous  clay. 
Gray-brown  clay  with  good  lamination,  though  with  some 

slidden  zones. 
Depth  to  bottom  unknown. 

Series    measured:    3023-3068,     3172-3264,     3342-3385, 
3462-3595,  3564-3713,  3605-3641,  3796-3836. 


4. — 3>^  miles  NNE  of  Hartford,  brickyard  at  Wilson. 

The  clay  is  covered  by  3  feet  of  sand.  The  topmost  7  feet  oi 
it  are  disturbed.  The  color  is  gray-brown  with  thin  red 
zones.  Lamination  is  good.  Depth  to  bottom  is  unknown, 
but  no  doubt  great. 

Series  measured:  3094-3261,  3462-3501,  3508-3559. 


5. — 5  miles  NE  of  Hartford,  South  Windsor,  brickyard  on 
Podunk  River  and  the  railroad. 

The  clay  is  covered  by  7  feet  of  sand.  It  is  gray-brown.  The 
lamination  is  particularly  good.  Depth  to  bottom  is 
unknown.  At  the  railroad  bridge  the  clay  is  said  to  be 
more  than  90  feet  thick. 

Series  measured:  3 173-3871. 


DESCRIPTION  OF  SECTIONS  13 

6. — 7  miles  NE  of  Hartford,  East  Windsor  Hill,  brickyard  on 

Stough ton's  Brook  and  the  railroad. 

The  clay  is  covered  by  7  feet  of  sand.   The  lamination  is  good. 
The  depth  to  the  bottom  of  the  clay  is  no  doubt  considerable. 

Series  measured:  3341-3616,  3565-3731,  3681-3854- 

7. — 2^   miles   SE   of   Springfield    (railroad   station),    Mass., 
Forest  Park,  brickyard  on  Pecowsic  Brook. 

5  feet  unlaminated  sand. 

13  feet  varve  sand,  not  measured. 

Silt,   varves  3623-3766.     Varves  in  many  cases  sandy  and 

valueless;  probably  deposited  in  too  strong  current. 
Light-gray  silt  with  good  varves. 
Depth  to  bottom  unknown. 

Series    measured:    3450-3623,     3459-3840,    3543-3590, 
(3623-3766)1 

8. — K  mile  N  of  Springfield,  brickyard  on  Carew  Street. 

6-12  feet  unlaminated  sand. 

8  feet  varve  sand,  not  measured. 

Sandy  varve  silt,   often  with  layers  of  quicksand.    Winter 

layers  thin,  dark  brown. 
Depth  to  bottom  unknown. 

Series    measured:    3758-3930,    3880-3930,    (3931-4013, 
3931-4014,  4027-4108). 

9. — Chicopee,  Mass.,  brickyard  at  the  southern  edge  of  the  city. 
Two  sections  were  measured: 

A. — ^An  abandoned  clay  pit  S  of  the  brickyard,  on  the 
highway  to  Springfield. 

10  feet  unlaminated  sand. 

12  feet  sandy  varve  silt  with  lenses  of  sand,  not  measured. 

Sandy  silt,  varves  3782-3870,  not  used  in  the  construction  of 

the  curve. 
Depth  to  bottom  unknown. 

2  Parentheses  indicate  that  the  varves  have  been  used  only  in  correcting,  not  in 
constructing  the  normal  curve. 


14  ICE  RECESSION  IN  NEW  ENGLAND 

9. — Continued 

B. — Clay  pit  E  of  the  yard. 
4  feet  unlaminated  sand. 
Varve  clay  containing  a  few  sandy  zones  and  becoming  sandy 

towards  the  bottom  of  the  section. 
Depth  to  substratum  unknown. 

Series  measured:  3798-4120,  4006-4053. 

10. — iK  miles  S  of  Holyoke  (railroad  station),  Mass.,  Williman- 
sett,  Holyoke  Brick  Co.'s  yard  on  Crowfoot  Brook  and 
the  railroad. 

12  feet  unlaminated  sand. 

Sandy  varve  silt  with  some  thin  disturbed  zones. 

Depth  to  bottom  unknown. 

Series  measured:  3931-4083,  4093-4i54»  (4155-4181). 

II. — I  mile  NNE  of  Holyoke,  South  Hadley  Falls,  Lynch  Brick- 
yard, abandoned  clay  pit  SE  of  the  yard. 

45  feet  sand,  mostly,  if  not  all,  varve  sand.  One  thin  winter 
layer  observed  12  feet  up;  all  other  winter  layers  seem  to 
have  been  eroded  away  during  the  springs  following  their 
deposition. 

4K  feet  sand,  varves  4290-4294,  thickest  varve  2  feet. 

Varve  silt,  somewhat  sandy.    Lamination  good. 

Depth  to  bottom  unknown. 

Series  measured:  4156-4264,  (4265-4294). 

12. — 250  yards  N  of  locality  11, 

Varve  silt  covered  by  a  few  sandy  varves.  Depth  to  bottom 
is  unknown. 

Series  measured:  4220-4264,  4224-4264,  (4265-4292). 

13. — 500  yards  N  of  locality  11,  Lynch  Brickyard,  pit  N  of  the 
crossroads. 

The  clay,  which  is  silty,  shows  very  good  lamination.  It  is 
covered  by  3  feet  of  sand.    Depth  to  bottom  is  unknown. 

Series  measured:  4099-4261. 


DESCRIPTION  OF  SECTIONS  15 

14.— 200  yards  N  of  locality  13,  Hampshire  Brick  Co.'s  yard. 

A  few  feet  of  varve  sand. 

Varve    silt,    changing    downwards    into    clay,    which    finally 

becomes  fat.   Lamination  very  good. 
iK  feet  slidden  clay,  probably  representing  only  a  few  varves. 
Gravel  and  cobbles  at  the  bottom  of  the  clay  pit.    Varve  clay 

is  said  to  occur  beneath  and  to  extend  to  unknown  depth. 

Series  measured:  3903-4256,  (4257-4273). 

15. — 3  miles  NNE  of  Holyoke,  South  Hadley,  ravine  on  Stony 
Brook  at  the  southern  edge  of  the  village,  200  yards  W 
of  the  highway. 

More  than  20  feet  sand. 

4  feet  disturbed  varve  clay. 

Red-brown  clay  in  thin,  typical  varves,  numbers  4405-4656. 

Silt  and  sand,  varves  4397-4404. 

Sand  somewhat  coarser  than  quicksand,  with  varves  up  to 

SK  feet  in  thickness,  numbers  4357-4396  (cf.  p.  51). 
Silt  and  quicksand  in  thick  varves,  numbers  4296-4356. 
Depth  to  bottom  considerable. 

Series    measured:     4305-4356,     4305-4356,    441 1-4600, 
(4289-4304,  4357-4410,  4357-4375,  4601-4656). 

16. — ^  mile  NW  of  locality  15,  bluff  on  Stony  Brook. 

2  feet  till  with  several  lo-inch  cobbles,  probably  carried  there 
by  an  iceberg. 

3  feet  weathered  varve  clay. 

Clay  with  good  lamination,  varves  4405-4630. 
Varve  sand  down  to  the  level  of  the  brook. 
Depth  to  bottom  considerable. 

Series  measured:  4405-4600,  (4387-4404,  4601-4630). 

17. — 41^  miles  N  of  Westfield,  Mass.,  brickyard  on  the  railroad. 

Two  sections  were  measured : 

A. — The  eastern  clay  pit. 

Silt  with  winter  layers  so  thin  that  the  varve  limits  are  very 
difficult  to  distinguish.  The  silt  is  covered  by  3  feet  of 
coarse  sand.    Depth  to  bottom  is  unknown. 

Series  measured:  (3780-3885). 


i6  ICE  RECESSION  IN  NEW  ENGLAND 

17. — Continued 

B. — The  western  clay  pit. 

5  feet  coarse  sand. 
4  feet  disturbed  silty  varve  clay. 
Clay  with  good  lamination. 
Depth  to  bottom  unknown. 

Series  measured:  3889-3966,  3890-3966,  (3967-3988, 
3967-3973). 

18. — 4  miles  SSW  of  Northampton   (railroad  station),  Mass., 

I  mile  E  of  Easthampton,  brickyard  on  the  road  and  the 

brook. 

Lamination  is  very  fine,  but  several  zones  are  strongly  dis- 
turbed. One  measurement  extends  to  5  feet  below  the 
brook.    Depth  to  substratum  is  unknown. 

Series  measured:  4228-4327,  4254-4324,  4304-4327, 
4342-4440,  4342-4413,  4342-4375,  4497-4610,  4715-4755, 
4766-4845,  (4846-4965,  4853-5104). 

19. — 1)4  mile  SW  of  Northampton,  brickyard  at  the  southwest- 
ern edge  of  the  city,  on  the  railroad  and  the  trolley  line  to 
Easthampton. 

8  feet  varve  sand  with  lenses  of  sand,  not  measured. 

Silt,  sandy  near  the  top  since  deposited  in  too  shallow  water, 

varves  5243-5490. 
Fat  clay  with  very  good  lamination,  though  with  many  slidden 

zones. 
Depth  to  bottom  unknown. 

Series  measured:  4556-4618,  4571-4885,  4591-4620, 
4673-4743,  4652-4834,  4768-4826,  4785-4813,  4785- 
4813,  4785-4813,  (5243-5490). 

20. — i}i  mile  WNW  of  Northampton,  brickyard  off  Elm  Street 
at  the  junction  of  Florence  and  Bay  State  roads. 

3  feet  sand. 

2  feet  weathered  and  disturbed  varve  clay. 
iK  feet  clay,   no  varves,  not  connected  with  the  normal 
curve. 


DESCRIPTION  OF  SECTIONS  17 

13  feet  silty  clay,  homogeneous  through  disturbance. 

4  feet  quicksand,  slidden  at  the  top,  varves  4633  and  4634 

(cf.  p.  79). 
Silty  clay,  sandy  at  the  top.   Lamination  good. 
Depth  to  bottom  unknown. 

Series    measured:    4377-4549,    4556-4585,    4556-4585 
(458M633)- 

21. — i^  miles  N  of  Northampton,  brickyard  on  the  railroad  at 

the  sharp  bend  of  the  Connecticut  River. 

The  clay  is  covered  by  3  feet  of  sand.  The  varves  are  very 
distinct,  but  the  clay  has  many  and  broad  disturbed  zones. 
Depth  to  bottom  is  no  doubt  considerable. 

Series  measured:  461 1-4633,  4611-4661,  4703-4772, 
4703-4744»  4775-4798,  4801-4910,  4806-4911,  4823-4840, 
4832-4910,4870-4902  4876-4909,  5243-5278,  5243-5269, 

5396-5479,  5398-5479,  (4565-4585)- 

22. — y^  mile  N  of  locality  21,  slide  on  the  western  side  of  the  big 

oxbow  of  the  Connecticut  River. 

The  clay  is  covered  by  10  feet  of  sand.  It  is  gray-brown  in 
■?olor  and  well  laminated,  but  many  and  broad  zones  are 
disturbed.  About  20  feet  above  the  river  level  the  clay 
passes  into  varve  sand,  which  extends  to  unknown  depth, 

Series  measured:  4617-4683,  4628-4683,  5243-5416, 
(4569-4594,  4818-4878,  5417-5497). 

23. — 2  miles  ENE  of  Northampton,   i  mile  S  of  Hadley,  the 

eastern  bank  of  the  Connecticut  River  at  the  sharp  bend. 

The  clay  is  covered  by  15  feet  of  sand.  It  is  fat,  gray-blue, 
well-laminated,  though  with  one  or  two  slidden  zones. 
Measurements  extend  down  to  2  feet  below  river  level. 
The  depth  of  the  clay  is  unknown. 

Series  measured:  4845-4877,  4854-4959,  4892-4952, 
4892-5046,  4948-5170,  4995-5110,  5043-5209,  5141-5222, 
5243-5280,  5244-5290,  5260-5446,  5455-5510. 


i8  ICE  RECESSION  IN  NEW  ENGLAND 

24. — 2  miles  SE  of  Amherst,  Mass.,  clay  pit  W  of  the  railroad 
tracks. 

2M  feet  till. 

2%  feet  crumpled  clay. 

10  feet  excellent  varve  clay. 

iK  feet  till. 

More  than  iK  feet  quicksand. 

Series  measured:  4461-4668,  (4450-4460). 
As   explained   on   page   79,    the   overlying   till    most 
probably  marks  a  readvance  of  the  ice  edge.     Tie 
lower  till  may  only  represent  a  small  readvance  during 
the  winter  following  the  deposition  of  the  sand. 


25. — ^A  few  hundred  yards  SE  of  locality  24,  clay  pit  at  the 
eastern  railroad  track. 

The  clay  is  covered  by  2>^  feet  of  sand.    Depth  to  bottom  is 
unknown. 

Series  measured:  4537-4588,  4617-4685. 


26. — Greenfield,  Mass.,  brickyard  at  the  western  edge  of  the 
town,  off  Elm  Street. 

Typical  silty  varve  clay,  although  towards  the  top  the  winter 
layers  are  so  thin  that  some  varve  limits  are  difficult  to 
distinguish.  Depth  to  substratum  is  unknown,  but  probably 
not  great. 

Series    measured:    5 119-5500,     5128-5203     5220-5256, 
5331-5365- 

27. — 2  miles  E  of  Greenfield,  old  brickyard  E  of  Montague  City, 
on  the  highway  running  eastward. 

The  silty  clay  is  distinctly  laminated.  It  is  covered  by  10  or 
more  feet  of  sand.    Depth  to  bottom  is  unknown. 

Series  measured:  5254-5456,  (52 11-5253). 


DESCRIPTION  OF  SECTIONS         _  19 

28. — 600  yards  N  of  locality  27,  brickyard  between  Montague 
City  and  Turners  Falls. 

8  feet  unlaminated  sand. 

8  feet  varve  sand. 

Gray  silty  clay  with  several  thick  sandy  varves,  most  of  which 
may  represent  drainages.  Lamination  very  good  except 
towards  the  top,  where  many  of  the  varves  are  wavy  and 
the  winter  layers  very  thin. 

Depth  to  bottom  unknown. 

Series  measured:  5084-5500  (drainage  varves  not  used  in 
the  curve),  (55oi-557o)- 

29. — On  the  Connecticut  River  <\^  miles  N  of  the  Massachusetts 
boundary,  railroad  cut  500  yards  NW  of  Fort  Hill 
station,  N.  H. 

15  feet  gravel  and  sand. 

Gray   silt   with    dark   winter   layers.     Thick   varves   sandy. 

Measurement  extends  down  to  4  feet  above  the  rails. 
Depth  to  bottom  unknown. 

Series  measured :  5438-5600,  (5601-5613). 

30. — Keene,  N.  H.,  old  brickyard  at  the  southern  edge  of  the 

city,  a  few  hundred  yards  E  of  the  railroad  bridge  across 

the  Ashuelot. 

In  May,  192 1,  the  clay  pits  were  filled  with  water  so  that 
only  a  short,  partly  disturbed  section  was  accessible.  The 
sediments  consist  of  graj^  silt  with  very  thin  winter  layers. 

Series  measured:  5804-5879,  (5687-5733). 

31. — 9  miles  NNE  of  Brattleboro,  Vt.,  brickyard  400  yards  W 

of  Putney  station, 

S  feet  sand  and  silt. 

Varve  silt,  at  the  very  top  sandy,  varves  6176-6277.    Winter 

layers  very  thin. 
Sandy  silt  with  very  thin  winter  layers,  varves  6100-61 75. 
Thick  silty  clay  with  excellent  lamination. 
Depth  to  bottom  unknown. 

Series    measured:    5713-6277,    6088-6277,     6094-6179, 
6246-6277. 


20  ICE  RECESSION  IN  NEW  ENGLAND 

32. — 8  miles  S  of  Bellows  Falls,  Vt.,  3  miles  N  of  East  Putney 
station,  railroad  cut. 

12  fe  t  /   '^^^^^^^  gravels  with  cobbles  4  inches  in  diameter. 

\  Sand. 
Well-laminated  silt.    Average  thickness  of  varves  3  inches. 
Depth  to  bottom  considerable. 

Series  measured:  (5941-6020). 

Sections  32  to  40  have  not  been  used  in  constructing 
the  normal  curve,  because  the  varves,  which  show  good 
correspondence,  are  too  thick. 

33. — 600  yards  N  of  locality  32,  2}^  miles  S  of  Grout  starion, 

railroad  cut. 

10  feet  gravel  and  sand. 

10  feet  slidden  silty  clay. 

Silty  clay.   Average  thickness  of  varves  4  inches. 

Depth  to  bottom  unknown. 

Series  measured :  (5869-5893). 

34. — 6>^  miles  S  of  Bellows  Falls,  2  miles  S  of  Grout  station, 

brook  ravine  100  yards  W  of  the  railroad  and  the  highway. 

i}4  feet  sand. 

3  feet  coarse  gravel  with  boulders  up  to  10  inches  in  diameter. 

9  feet  sand. 

Typical  silty  varve  clay;  towards  the  bottom  varve  sand. 

Some  disturbed  zones  near  the  bottom.    Average  thickness 

of  varves  about  3K  inches. 
Bed  rock. 

Series  measured:  (58o2?-5828?,  5865-5970). 

The  number  of  the  bottom  layer  is  about  5797. 

35. — 5  miles  SSW  of  Bellows  Falls,  i  mile  SW  of  Grout  station, 

bluff  on  the  brook  just  W  of  the  highway. 

12  feet  gravel,  and  sand. 

Gray  silt  with  excellent  lamination.    The  topmost  horizons 

much   disturbed.     Average   thickness   of   varves   about   3 

inches. 
The  silt  continues  to  unknown  depth  below  the  brook. 


DESCRIPTION  OF  SECTIONS  21 

Series  measured:  (6006-6150,  6006-6087,  6094-6193, 
6094-6138,  6114-6152,  6117-6156,  6200-6234,  6240- 
6250). 


36  __2^  miles  S  of  Bellows  Falls,  %  mile  N  of  Westminster 
station,  slide  just  W  of  the  highway  and  250  yards  W  of 
the  railroad. 

The  varve  silt  is  covered  by  17  feet  of  sand.  Average  thickness 
of  varves  3K  inches.    Depth  to  bottom  is  considerable. 

Series  measured:  (6 193-62 14). 

3y,_2^  miles  SSW  of  Bellows  Falls,  i3<  miles  WNW  of  West- 
minster station,  bluff  on  the  northern  branch  of 
brook  yi  mile  W  of  the  point  where  it  joins  the  southern 
one  250  yards  W  of  the  highway. 

12  feet  unlaminated  sand. 
3  feet  varve  sand,  varves  6261-6276. 

Silt,  varves  6212-6260.    Average  thickness  of  varves  5  inches. 
Varve  sand  with  lenses  from  50  feet  above  the  brook  and 
downward.    Lower  part  of  bluff  covered  by  talus. 

Series  measured:  (6212-6276). 

This  section  is  not  used  in  the  construction  of  the 
standard  curve. 

38. — 6  miles  N  of  Bellows  Falls,  Vt.,  i>^  mile's  SW  of  Charles- 
town,  N.  H.,  bluff  on  the  western  side  of  the  Connecticut 
River. 

3  feet  fine  unlaminated  sand. 

2%.  feet  gravel. 

5  feet  silt  to  fine  sand. 

Varve  silt,   the   thickest   varves   sandy.     Lamination   good. 

Average  thickness  of  the  varves  i  foot. 
Sediments  extend  to  unknown  depth  below  the  river. 

Series  measured:  (6 163-62 18). 


THE  aiHERINE  B.  O'CONNOR  LIBRAP 

WESTON  OBSERVATORY 

WESTON  93    MKCTU   r^,xf 


22  ICE  RECESSION  IN  NEW  ENGLAND 

39. — yi  mile  N  of  locality  38,  slide  in  a  ravine  100  yards  W  ol 
the  river. 

The  distinctly  laminated  silt  is  covered  by  8  feet  of  sandy  silt. 
The  accessible  section  begins  25  feet  above  the  river  level, 
the  lower  part  being  covered.  The  average  thickness  of  the 
varves  is  somewhat  less  than  a  foot. 

Series  measured:  (6086-6136). 

40. — Charlestown,  N.  H.,  bluff  on  the  Connecticut  River  directly 

W  cf  the  railroad  station. 

7  feet  river  gravel. 

Varve  silt  with  some  disturbed  zones.    Average  thickness  of 

varves  8  to  10  inclies. 
More  than  7  feet  glacial  gravel. 

Series  measured:  (6007-6034,  6069-6083). 

Varve  6007  is  bottom  varve. 

41. — 5  miles  SSW  of  Claremont,  N.  H.,  bluff  on  Little  Sugar 
River  600  yards  W  of  North  Charlestown  station. 

4  feet  coarse  gravel,  in  V\rhich  boulders  4  to  8  inches  in  diameter 
constitute  half  the  deposit.  Several  boulders  are  a  foot  in 
diameter.    One  block  measured  i  foot  4  inches. 

I  foot  sand. 

Discordance. 

Varve  sand  extending  to  unknown  depth  below  river  level. 
Average  thickness  of  varves  10  inches. 

Measurements  include  one  series  of  50  and  another  of 
30  varves  from  the  same  horizon.  The  series  are  not 
connected  with  the  normal  curve. 

The  gravel  at  the  top  is  probably  outwash  indicating 
a  readvance  of  the  ice  edge  (cf.  p.  81). 

42.— >^  mile  NNE  of  locality  81,  sand  pit  on  the  highway  to 
Claremont. 

Silt  with  varves  on  an  average  7  inches  thick. 

Series  measured:  25  varves  corresponding  to  the  series 
at  locality  41. 


DESCRIPTION  OF  SECTIONS  23 

43- — %  mile  WSW  of  Claremont  Junction,  N.  H.,  day  pit  on 
the  road. 

10  feet  sand  and  silt. 

Sandy   varve   silt   with    very   thin"  winter   layers.     Average 

thickness  of  varves  2^   to  3   inches.     One  or  two  zones 

disturbed. 
Depth  to  bottom  considerable. 

One  series  of  70  and  another  of  100  varves  measured  from 
the  same  horizon.  The  series  are  not  connected  with 
the  normal  curve. 

Localities  in  the  Merrimac  Valley 

44.-7  miles  SSE  of  Concord   (railroad  station),   N.   H.,   old 

brickyard  halfway  between  Suncook  and  Hookset. 

The  clay  is  covered  by  5  feet  of  sand.    It  contains  several 
disturbed  zones.    Depth  to  bottom  is  unknown. 

Series  measured:  (5764-5791,  5804-581 1,  5850-5875)- 

45- — 4K  rniles  SE  of  Concord,   old  brickyard  on   the  brook 
between  the  Merrimac  River  and  Pembroke. 
3  feet  weathered  clay. 
Clayey  silt  with  excellent  lamination. 
3  to  6  feet  down  to  till,  which  shows  in  the  brook. 

Series  measured:  5709-5749. 

46. — 2  miles  S  of  Concord,  clay  pits  400  to  700  3'ards  W  of  Bow 
Junction. 

Surface  of  wash  plain. 

10  feet  sand. 

Sandy  silt,   varves  somewhat  wavy  since   deposited   in   too 

shallow  water,  numbers  6308-6352.    Winter  layers  hardly 

distinguishable. 
Excellent  clay,  varves  5771-6307. 
Sand  to  silt,  somewhat  slidden.     14  varves  of  an  average 

thickness  of  sH  inches. 
8  to  10  feet  down  to  till,  which  appears  in  the  brook  close  by. 

The  lowest  horizons  measured  700  yards  W  of  Bow  Junction, 

just  N  of  the  highway  bridge  across  the  brook. 

Series  measured:  5771-6332,  6233-6352,  6305-6352. 


24  ICE  RECESSION  IN  NEW  ENGLAND 

47' — 2  miles  SE  of  Concord,  bluff  on  the  eastern  side  of  the 
sharp  bend  of  the  Merrimac  River. 
10  feet  sand. 

2  feet  disturbed  varve  clay. 

Sandy  clay,  often  with  lenses  of  sand,  varves  6009-6095. 
Very  good,  silty  clay,  varves  5914-6008. 
13  feet  talus  down  to  river  level.   Depth  to  bottom  unknown. 

Series  measured:  (5914-5974,  5980-6095). 
The  greater  part  of  the  curve  shows  typical  variation, 
but  it  has  not  been  used  in  the  construction  of  the 
normal  curve,  since  the  varves  are  too  thick.  The 
same  is  the  case  with  many  other  sections  in  the 
Merrimac  Valley. 

48. — I  mile  SE  of  Concord,  400  yards  E  of  the  highway  bridge 
across  the  Merrimac  River,  just  S  of  the  highway. 

The  clay  is  covered  by  13  feet  of  sand.  The  uppermost  6  feet 
of  the  clay  are  slidden.   Depth  to  bottom  is  considerable. 

Series  measured:  (6267-6304), 

49. — >^  mile  ESE  of  Concord,  old  brickyard  on  the  eastern  side 
of  the  Merrimac  River,  at  the  bend. 

The  clay  is  cove-ed  by  3  to  6  feet  of  sand.  Several  varves 
are  sandy,  and  the  thicknesses  are  not  so  good.  At  the 
bottom  of  the  pit  the  varves  are  thick  and  sandy,  probably 
indicating  inconsiderable  depth  to  substratum.  Several 
zones  are  slidden. 

Series    measured:    (5791-5830,    5794-5829,    5808-6047, 
5839-5872,  5883-5937,  5948-5987). 

50. — I  mile  NE  of  Concord,  bluff  on  the  eastern  side  of  the 
Merrimac  River,   500  yards  N  of  the  state  highway 
running  from  Concord  eastward. 
Surface  of  wash  plain. 
50  feet  sand. 

Varve  sand ;  1 5  varves  from  2  inches  to  8  feet  thick. 
16  feet  covered  by  talus. 
At  the  level  of  the  river  varve  quicksand;  varves  8  inches  thick. 

Thus  far  I  have  not  been  able  to  connect  this  section 
with  the  normal  curve. 


DESCRIPTION  OF  SECTIONS  25 

51. — yi  mile  N  of  locality  50,  Sugar  Ball  Bluff  on  the  eastern 
side  of  the  Merrimac  River,  at  the  sharp  bend. 

Surface  of  wash  plain. 

30  feet  sand. 

Varve  sand;  5  varves  varying  from  1%  inches  to  8  feet  in 

thickness. 
50  feet  (varve  sand?)  covered  by  talus. 
At  river  level  varve  silt;  10  varves  averaging  iK  inches  in 

thickness. 

The  series  is  not  connected  with  the  normal  curve. 


52. — 7  miles  NNW  of  Concord,  yi  mile  NW  of  Boyce  station, 
bluff  on  the  eastern  side  of  the  Merrimac  River. 

Surface  of  wash  plain. 

60  feet  of  sand,  mostly  covered  by  talus,  perhaps  partly  varve 

sand. 
Varve  sand,  varves  6232-6243;  average  thickness  i  foot. 
Silt  and  quicksand,  varves  622 1-623 1;  average  thickness  3 

inches. 
Good  silty  varve  clay. 
Talus  extending  13  feet  down  to  the  river  level. 

Series   measured:    6105-6141,    6163-6220,    (6142-6162, 
6221-6243). 


53. — 250  yards  NE  of  locality  52,  bluff  on  the  Merrimac  River 
and  ravine  75  yards  E  of  the  bluff  and  75  yards  W  of  the 
railroad. 

Surface  of  wash  plain. 

50  feet  sand,  mixed  with  some  gravel. 

Varve  sediments;  thick  varves  consisting  of  sand,  thin  varves 

of  silt  or  sandy  silt;  thickness  varying  from  i>^  inches  to 

Z%  feet. 
Talus  10  feet  down  to  river  level. 

One  series  of  45  and  another  of  38  varves  were  meas- 
ured on  the  same  horizon.  They  are  not  connected 
with  the  normal  curve. 


26  ICE  RECESSION  IN  NEW  ENGLAND 

54. — 7>^  miles  NNW  of  Concord,    i   mile   NW  of  Penacook 

station,  gravel  pit  just  W  of  the  railroad,  400  yards  S 

of  the  bend  of  the  Merrimac  River  which  lies  close  to 

the  railroad. 

2)4.  feet  sand. 

iK  feet  varve  sand,  disturbed. 

2  feet  sandy  varve  silt,  partly  disturbed. 

Silty  clay,  varves  5942-6177.    Two  zones  disturbed. 

3  inches  slidden  zone. 
Varve  sand,  15  varves. 

Depth  to  bottom  probably  inconsiderable. 

Series    measured:    5942-5985,    5995-6124,    6144-6177, 
(6178-6201). 

55. — 250  yards  N  of  locality  54,  bluff  on  the  western  side  of  the 

Merrimac  River,  150  yards  S  of  the  bend  of  the  river. 

The  clay  is  covered  by  10  feet  of  sand  and  gravel.  The  lamina- 
tion is  excellent.  The  clay  continues  to  unknown  depth 
below  the  river  level. 

Series    measured:    6004-6177,    6184-6220,    (6178-6183, 
6221-6234). 

56. — 350  yards  NE  of  locality  55,  bluff  on  the  eastern  side  of  the 

Merrimac  River. 

The  well-laminated,  gray  clay  is  covered  by  5  feet  of  fine 
gravel.    It  continues  to  unknown  depth  below  the  river. 

Series  measured:  5987-6220,  (5937-5986,  6221-6247). 

57. — y^  mile  NNE  of  locality  56,  bluff  on  the  eastern  side  of  the 
Merrimac  River.    Three  sections  were  measured: 

A. 

Surface  of  wash  plain. 

25  feet  sand,  towards  the  north  much  thicker,  as  the  under- 
lying varve  sand  dips  that  way. 
Varve  sand,  20  varves,  from  6  inches  to  7  feet  in  thickness. 
40  feet  talus  down  to  the  river  level. 

The  varve  series  corresponds  to  the  lower  part  of  sec- 
tion 53.    It  is  not  connected  with  the  normal  curve. 


DESCRIPTION  OF  SECTIONS  27 

B. 

Surface  of  wash  plain. 

About  100  feet  sediments,  not  exposed  (sand?). 

Varve  silt  and  sand,  varves  6306-6321.    Thicknesses  varying 

from  3  inches  to  iK  feet.    The  lowest  varve  measured  5 

feet  above  the  river. 

Series  measured:  (6306-6321). 

C. 

Surface  of  wash  plain, 

100  feet  sediments,  not  exposed  (sand  ?). 

Varve  silt,  varves  6267-6303.    Average  thickness  2%  inches. 

3  feet  talus  down  to  river  level. 

Series  measured:  (6267-6303). 

58.—  10  miles  NNW  of  Concord,  clay  pit  at  the  schoolhouse 

yi  mile  NW  of  Canterbury  station. 

Cut  in  the  upper  part  of  silty  sediments.    Thickness  of  varves 
varying  from  i  to  9  inches. 

Series  measured :  (6265-63 12). 

59. — II  miles  NNW  of  Concord,  2  miles  N  of  Boscawen,  railroad 

cut. 

3  feet  sand. 

2%  feet  sandy  varve  silt. 

Characteristic  clay,  somewhat  silty,  varves  6003-6232. 
Varve  sand  and  silt,  varves  5989-6004.    Varve  5989  more 
than  2%.  feet  thick,  the  others  varying  from  3  to  10  inches. 
25  feet  talus  ending  at  the  stony  bottom  of  a  brook. 

Series  measured:  6025-6232,  (5989-6024,  6233-6255). 

60. — Franklin,  N.  H.,  clay  pit  at  the  northwestern  edge  of  the 

village,  near  the  underpass  of  the  Mascoma  road. 

3  feet  varve  silt  with  lenses,  not  measured. 

Silt.   The  topmost  varve  3  feet,  the  lowest  i  foot  2  inches  and 

the  rest  from  i  inch  to  i  foot  in  thickness. 
Depth  to  bottom  unknown. 

Series  measured :  (6162-6185). 


28  ICE  RECESSION  IN  NEW  ENGLAND 

Localities  in  the  Connecticut  Valley  (Continued) 

6i. — 5  miles  S  of  Windsor,  Vt.,  bluff  on  the  brook  S  of  Ascutney- 
ville,  between  the  highway  and  the  Connecticut  River. 
Plain  of  sedimentation. 
4  feet  gravel. 
2  feet  sand  and  silt. 

Varve  sediments,  silt  in  the  upper  half,  sand  in  the  lower  half. 
25  feet  glacial  gravel. 
Bed  rock. 

Series  measured:  6601-6662,  (6608-6638). 

In  the  same  bluff,  a  little  to  the  east,  the  section  is 

essentially  different  because  of  disturbances  and  down- 

slidden  horizons. 

Number  6601  is  bottom  varve. 

62. — 3  miles  NW  of  Claremont,  N.  H.,  bluff  on  the  highway, 
just  W  of  the  junction  of  the  Sugar  River,  the  railroad, 
and  the  highway. 

The  material  is  silty.   The  thickness  of  the  varves  varies  from 
6  inches  to  2}^  feet.    Depth  of  the  deposit  is  unknown. 

Series  measured :  (66 1 3-663 1 ) . 

63. — 3}4  miles  NW  of  Claremont,  K  i^iile  N  of  the  railroad 
bridge  across  the  Sugar  River,  where  the  railroad  crosses 
Walter  Brook. 

Several  measurements  were  carried  out   in  slides  in 
the  deep  brook  ravine  as  far  as  J/2  mile  NNE  of  the  rail- 
road as  well  as  in  the  railroad  banks  N  and  S  of  the  brook. 
600  yards  NNE  of  the  railroad  the  profile  was  like  this: 
Plain  of  sedimentation. 
15  feet  sand. 

Varve  silt  to  sand  with  thin  winter  layers,  varves  6806-7073- 
Varve  clay  to  silt  with  very  good  lamination,  varves  6642- 

6805. 
Varve   silt,   somewhat   sandy,   with   several   slidden   zones. 
Thickness  of  varves  from  2  inches  to  2  feet.  About  30  varves 
measured  but  not  connected  with  the  normal  curve. 
6  feet  talus  down  to  the  brook.   Depth  to  substratum  probably 
inconsiderable. 


DESCRIPTION  OF  SECTIONS  29 

Series  measured:  6642-6662,  6643-6666,  6647-6713, 
6648-6658,  6680-6706,  6690-6805,  6714-6823,  6726-6823, 
6811-6823,  6858-6981,  6858-6922,  6858-6898,  6858-6871, 
6894-7073,  6930-6980. 

64. — I  mile  SSE  of  Westboro,  N.  H.,  ravine  on  the  southern  side 
of  the  Mascoma  River,  S  of  the  first  railroad  bridge  across 
the  river. 

Plain  of  sedimentation. 

4  feet  fine  sand. 

Typical  varve  clay. 

80  to  100  feet  till  down  to  the  river. 

Series  measured:  6750-6802,  (6734,  bottom  varve  -6749). 

65. — I  mile  SE  of  Westboro,  cut  on  the  road  150  yards  NE  of 
the  new  bridge  across  the  Mascoma  River  and  the 
railroad. 

The  clay  shows  good  lamination.  Depth  to  bottom  is  unknown. 

Series  measured:  (6760-6801). 

66. — %  mile  N  of  White  River  Junction,  Vt.,  ravine  just  W  of 
the  railroad. 

The  clay  shows  rather  good  lamination.  It  is  covered  by  4 
feet  of  sand.  Below  the  measured  series  the  varves,  which 
are  slidden,  become  thick  and  silty.  Depth  to  substratum 
is  more  than  30  feet. 

Series  measured:  6783-6888. 

67.—%  mile  SSE  of  Hanover,  N.  H.,  bluff  on  Mink  Brook. 

25  feet  sand  and  silt,    Varve  limits  hardly  distinguishable. 

Varves  6806-7040,  silty,  often  sandy  and  with  lenses  of  sand. 
Varve  limits  often  very  difficult  to  distinguish.  Thicknesses 
varying  greatly,  but  on  the  average  about  2  inches. 

Varves  6760-6805,  silty,  distinct.  Thickness  varying  from  i 
to  15  inches. 

Exposed  to  the  level  of  the  brook.  Depth  to  bottom  un- 
known. 

Series  measured :  (about  6760  to  about  7040;  only  varves 
6806-6862  have  been  used  for  control  of  the  number). 


30  ICE  RECESSION  IN  NEW  ENGLAND 

68. — ii>^  miles  NNE  of  Hanover,  300  yards  NE  of  Northboro 
station,  clay  pit  on  the  eastern  side  of  the  Connecticut 
River. 

About  10  feet  sand  and  silt. 

About  10  feet  clay  with  very  thin  varves  becoming  sandy 

upwards,  not  measured. 
Varves  6867-7021.    Average  thickness  about  ^  inch.     The 
thicknesses  not  characteristic,  and  the  profile  of  little  value. 
Disturbed  zone:  silt  with  rests  of  thick  varves. 
Depth  to  substratum  unknown. 

Series  measured:  (6867-7021). 

69. — iX  miles  E  of  locality  68,  bluff  on  Clay  Brook. 
Silt. 

15  feet  clay  with  very  thin  varves,  not  measured. 
Varves  6857-6957,  on  the  average  K  to  M,  inch  thick.    Thick- 
nesses not  characteristic. 
Disturbed  quicksand. 
Depth  to  bottom  unknown. 

Series  measured:  (6857-6957). 

70. — ^11  miles  SSW  of  Woodsville,  N.  H.,  i  mile  NE  of  Bradford, 
Vt.,  bluff  on  the  eastern  side  of  the  Connecticut  River, 
back  of  a  cemetery. 
Sand. 
Varve  clay.   High  and  fine  exposure,  not  measured  on  account 

of  lack  of  time. 
Varve  clay,  measured  down  to  river  level,  from  varve  7041 
and  upward  exceedingly  fat.  Lamination  good.  Varve  6901, 
if  not  bottom  varve,  is  practically  so.  Varves  6901-6903 
consist  of  quicksand.  Varve  6901  is  more  than  2  feet, 
varve  6902  6^  inches,  and  6903  10^  inches  thick. 

Series  measured:  6901-71 12. 

71. — 10  miles   SSW  of   Woodsville,  3   miles   SW  of   Haverhill 

station,  ravine  on  the  western  side  of  the  road,  close  to 

the  bend  of  the  Connecticut  River,  just  N  of  a  farmhouse. 

High  section  with  some  slidden  zones.  On  account  of  lack  of 
time  only  a  few  bottom  varves  were  measured.  The  clay 
rests  on  till.    Varve  6904  is  bottom  varve. 

Series  measured:  (6904-6912,  6027-6936). 


DESCRIPTION  OF  SECTIONS  31 

72. — 7  miles  S  of  Woodsville,  %  mile  N  of  Haverhill  station,  ra- 
vine on  the  western  side  of  the  highway. 

The  upper  20  feet  of  the  section  covered  by  turf.  The  clay  is 
very  fat  and  with  many  disturbed  zones.  The  underlying 
till  was  reached,  but  the  bottom  varves  are  missing  because 
of  landslide. 

Series  measured:  7009-7048,  (7049-7106,  7 130-7 174, 
7199-7228,  7236-7268,  7274-7304). 

73. — 7  miles  S  of  Wells  River,  Vt.,  i  mile  N  of  Conicut  station, 
brook  ravine  100  yards  W  of  the  railroad,  where  the  bend 
of  the  Connecticut  River  comes  close  to  the  railroad. 

Plain  of  sedimentation. 

20  feet  varve  sand,  about  30  varves. 

10  feet  varve  clay,  275  varves. 

io>2  feet  varve  clay,  900  varves. 

Varve  clay  with  good  lamination  but  with  some  disturbed 

zones,  measured. 
Level  of  the  brook.    Depth  to  substratum  unknown. 

Series  measured:  6990-7004,  7008-7087,  7 199-73 16. 

This  profile  shows  that  the  glacial  lake  was  in  existence 
for  at  least  1,600  years. 
74. — 6  miles  S  of  Wells  River,  one  clay  pit  i  mile  S  of  Newbury 
station  150  yards  W  of  the  railroad  and  another  300  yards 
farther  S  just  west  of  the  tracks. 

Small  sections  in  partly  disturbed  clay.  Varves  at  different 
horizons  slidden  away. 

Ssries  measured:  7008-7048,  7008-7042,  (7049-7066, 
7073-7 1 1 5). 

75- — 4/4  miles  S  of  Woodsville,  N.  H.,  bluffs  on  the  brook  300 
yards  S  and  W  of  Blackmount  station. 

The  clay  is  underlain  by  till.  The  sections  are  of  little  value, 
since  several  zones  are  slidden. 

Series  measured:  6930,  bottom  varve  -6941,  6967-7048, 
6967-6985,  7008-7029,  700Q-7048,  (7035-7088,  7049- 
7092,7147-7201). 


32  ICE  RECESSION  IN  NEW  ENGLAND 

76. — 2  miles  W  of  Wells  River,  Vt.,  brickyard  on  the  brook 
discharging  into  the  Wells  River.  De  Geer's  (1921) 
locality  'Wells  River."  De  Geer's  profile  was  measured 
on  a  series  of  samples  taken  by  R.  Liden. 

25  feet  sand. 

10  feet  varve  sand  to  silt.  Varves  on  the  average  i  inch  thick. 

Varve  limits  very  difficult  to  distinguish. 
Varve  clay,  varves  6970-7500.   Lamination  poorly  developed. 
Probably  not  far  down  to  bottom,  since  till  appears  in  the 

brook  close  to  the  section. 

Series  measured:  (6970-7500). 

Since  the  clay  was  very  difficult  to  measure,  and  my 
measurement  shows  little  agreem.ent  with  the  others 
from  the  region,  this  section  has  not  been  used  for 
the  correction  or  the  construction  of  the  normal 
curve. 

77. — ^W^ells  River,  300  yards  N  of  the  station,  cut  on  the  western 
side  of  the  highway. 

7  feet  silt  and  sand,  varves  about  i  foot  thick. 
7  feet  silty  clay,  varves  too  thin  to  be  measured  or  counted. 
3  feet  silty  clay,  often  with  sandy  layers,  about  200  varves. 
Fat  blue-gray  varve  clay  with  one  or  two  folded  zones,  varves 

7155-7290.    Average  thickness  about  K  inch.    Lamination 

good. 
12  feet  talus. 
Sand.    Depth  to  bottom  of  sediments  unknown. 

Series  measured:  (7155-7290). 

78. — ^Woodsville,  N.  H.,  brickyard  yi  mile  N  of  the  station. 
De  Geer's  (192 1)  locality  "Woodsville".  De  Geer's  sec- 
tion measured  by  R.  Liden. 

The  clay  pits  are  situated  at  the  foot  of  a  hill.  The 
appearance  of  the  profiles,  in  1916,  has  been  described 
in  detail  by  Sayles  (1919,  p.  18).  In  192 1  the  exposures 
were  not  quite  so  good. 


DESCRIPTION  OF  SECTIONS  33 

A. — ^The  western  day  pit. 

The  clay  rests  on  till.  The  150  lowest  varves  have  slidden 
away.  Many  zones  are  disturbed.  The  clay,  in  some  zones, 
is  exceedingly  fat  and  has  been  squeezed,  so  that  the 
thicknesses  of  many  varves  are  unreliable.  Consequently 
my  measurements  are  valueless. 

Series  measured:  (7100-about  7300). 

Beside  this  a  series  of  150  varves,  containing  3  thick 
slidden  zones;  these  varves  not  connected  with  the 
standard  curve. 

B. — ^The  eastern  clay  pit. 

The  clay  is  so  disturbed  that  no  part  of  my  measurement 
can  be  connected  with  the  normal  curve.  It  contains 
several  beds  of  till  which  may  have  slidden  down  from  the 
hill  that  rises  just  behind  the  section,  or  may  have  been 
brought  there  by  icebergs. 

79. — I  mile  N  of  Woodsville,  ravine  E  of  the  road.   The  lowest 
varves  were  measured  200  yards  SE  of  the  ravine. 
Weathered  clay. 

Silty  clay  with  very  distinct  lamination,  varves  7200-7262. 
Blue-gray   clay,    exceedingly   fat,    almost   like   green   soap, 

varves  7147-7199.    Thicknesses  of  varves  not  good. 
Fat  clay  with  good  lamination,  varves  7045-7146. 
Silty  clay  with  perfect  lamination,  varves  6967-7044. 
Fine  sand,  varves  6954-6966.   Varve  6954  is  probably  bottom 

varve. 

Series    measured:    6991-7146,    7199-7262,    (6954-6990, 
7147-7199). 

80. — 2)4  miles  NNW  of  Woodsville,  bluff  on  the  eastern  side  of 
the  Connecticut  River,  directly  opposite  Long  Meadow 
Farm. 

25  feet  sand. 

Good  varve  clay,  though  with  several  disturbed  zones  and 
one  or  two  zones  wholly  missing  without  leaving  any  trace 
in  the  section. 
Talus  reaching  20  feet  down  to  the  river. 

Series    measured:    6992-7131,    7154-7177,    (7200-7209, 

7215-7227,7253-7302). 


34  ICE  RECESSION  IN  NEW  ENGLAND 

8i. — 2>H  miles  N  of  Woodsville,  y^  ^^^^  S  of  East  Ryegate 
station  and  locality  82,  ravine  E  of  the  Connecticut 
River,  between  the  river  and  the  road. 

7  feet  sand. 

6  feet  clay,  partly  disturbed. 

High  section  of  good  varve  clay;  only  a  part  measured. 

Series  measured:  7147-7198. 


82. — 4  miles  N  of  Woodsville,  bluff  on  the  eastern  side  of  the 
Connecticut  River,  directly  opposite  East  Ryegate 
station. 

Plain  of  sedimentation. 

2  feet  gravel. 

Somewhat  silty  clay  with  good  lamination,  varves  7200-7328. 

Fat  blue  clay  with  very  distinct  lamination,  varves  6999-7199. 

50  feet  talus  down  to  river  level. 

Depth  to  substratum  unknown. 

Series  measured:  6999-7328. 

83. — 600  yards  N  of  locality  82,  bluff  on  the  western  side  of  the 

river. 

The  clay  is  covered  by  20  feet  of  sand.  It  contains  many 
deformed  zones.  It  continues  to  unknown  depth  below  the 
river. 

Series    measured:    (7213-7277,    7260-7321,    7307-7321, 
7323-7354). 

84.— The  junction  of  the  Connecticut  and  Passumpsic  Rivers, 

on  the  easternmost  channel  of  the  Connecticut,  300  yards 

upstream  from  its  junction  with  the  main  river. 

10  feet  sand,  gravel,  and  cobbles. 
25  feet  varve  clay,  not  measured. 
Exceedingly  fat  clay,  varves  7247-7338.    Varve  limits  often 

difficult  to  distinguish. 
The  clay  continues  below  river  level. 

Serif^s  measured:  (7247-7338). 


DESCRIPTION  OFJSECTIONS  35 

85. — y^  mile  E  of  the  junction  of  the  Connecticut  and  Pas- 
sumpsic  Rivers,  brook  ravine  100  yards  N  of  the  Con- 
necticut. 

Second  terrace  down  from  the  top. 
f   River  gravel  with  cobbles. 

7  f^^t  \   Sand. 

20  feet  sandy  varve  clay,  about  200  varves.  Varve  limits 
very  difficult  to  distinguish. 

Exceedingly  fat,  lead-colored  clay,  varves  7399  to  about 
7500.  Varve  limits  marked  by  hardly  distinguishable  light 
streaks  of  silt.    The  lowest  60  varves  thick. 

Fat  dark-gray  clay,  varves  7307-7398.  Varve  limits  often 
difficult  to  distinguish,  Varve  7307  consists  of  sharp  sand 
and  is  2K  feet  thick.  From  this  varve  it  is  3  to  4  feet  down 
to  till,  which  shows  in  the  bed  of  the  brook.  Consequently 
varve  7306  (or  7305)  may  be  bottom  varve. 

Series  measured:  7307-7400  (also  several  hundred  varves 
above  7400). 

86. — Inwood,  Vt.,  slide  200  yards  E  of  the  railroad  station. 

Plain  of  sedimentation. 

60  feet  covered  by  turf. 

Excellent  silty  clay,  varves  7214-7355. 

10  feet  covered  and  partly  slidden. 

Fat  clay  with  very  good  lamination,  varves  7059-7192. 

Sandy  clay,  varves  7036-7058. 

Series    measured:    7078-7192,     7214-7224,     7238-7294, 
7316-7355,  (7036-7077,  7225-7237,  7295-7315)- 

A  little  to  one  side  and  about  10  feet  lower  than  varve 
7036  a  series  of  8  silty  to  sandy  varves  with  thicknesses 
varying  from  i>^  to  6  feet  was  measured.  Bed  rock 
lies  about  10  feet  below  the  lowest  varve. 

87. — Inwood,  brook  ravine  500  yards  NNE  of  the  railroad  station. 
The  section  is  of  little  value  because  of  several  contorted  zones. 

Series    measured:    (7039-7046,    7082-7139.    7254-7274, 
7306-7320). 


36  ICE  RECESSION  IN  NEW  ENGLAND 

88. — Inwood,  600  yards  NNE  of  the  railroad  station,  slide  SE 
of  the  farmhouse. 

Topmost  terrace  or  plain  of  sedimentation. 

25  feet  sand  and  silt. 

Varve  sand  with  very  thin  winter  layers,  about  60  varves. 

Average  thickness  K  inch. 
Varve  silt  with  thin  winter  layers,  about  280  varves.   Average 

thickness  %  inch. 
Exceedingly  fat,  lead-colored  clay,  about  60  varves.   Average 

thickness  2%  inches.    The  two  lowest  varves  are  numbers 

7399  and  7400. 
Silty,  excellent  varve  clay,  varves  7288-7398. 
Talus.   Depth  to  substratum  unknown. 

Series    measured:    7288-7400,    (7401-about  7800)    and, 
close  by,  7254-7316. 

89. — Inwood,   1,000  yards  N  of  the  railroad  station,  slide  E 

of  the  road,  N  of  the  farmhouse. 

Gray    clay   with    excellent    lamination.     Depth    to    bottom 
considerable. 

Series  measured:  7 157-7 189,  7210-7357. 

90. — 100  yards  W  of  locality  89,  bank  on  the  western  side  of  the 
road. 

5  feet  weathered  and  slidden  varve  clay. 
Silty  clay,  varves  7200-7298. 
Very  fat  clay,  varves  7094-7199. 
Depth  to  bottom  considerable. 

Series  measured:  7094-7298. 

The  lamination  is  very  distinct. 

91. — 3  miles  S  of  St.  Johnsbury,  Vt.,  slide  400  yards  SE  of 
Passumpsic  station. 

20  feet  sediments,  covered  (mostly  sand  ?). 

Clay  with  clearly  defined  lamination,  varves  7082-7312. 

60  feet  of  sediments,  covered,  presumably  for  the  most  part 

silt  in  very  thick  varves. 
Bed  rock. 

Series  measured:    7096-7312,  (7082-7095). 


DESCRIPTION  OF  SECTIONS 


37 


Figs. 


Fig.  s 
5-12 — Maps  showing,  by  crosses  and  numbers,  the  position  of  the  localities 


examined  in  the  Connecticut  Valley.  Scale  1:160,000. 

Outlines  of  late  glacial  lakes  (area  left  white) :  in  Connecticut  after  G.  F.  Loughlin 
(iQOs);  in  Massachusetts  after  B,  K.  Emerson  (i8g8);  in  New  Hampshire  and 
Vermont  after  C.  H.  Hitchcock  (1878).  Topographic  base  from  same  sources. 
For  the  general  location  of  each  map,  see  the  index  map  on  Figs.  8,  g,  10,  or  12. 


38 


ICE  RECESSION  IN  NEW  ENGLAND 


Fig.  6 


DESCRIPTION  OF  SECTIONS 


39 


Fig.  7 


40 


ICE  RECESSION  IN  NEW  ENGLAND 


St.Johnsbury 


Fig.  8 


DESCRIPTION  OF  SECTIONS 


41 


/ /V~^\    ^^^"f  \  72120' 


St.Johnsbury 


MILES     1  2  3 

^T ,  I.,     ;l 


Fig.  9 


42 


ICE  RECESSION  IN  NEW  ENGLAND 


S+.Johnsbur^ 


Fig.  10 


DESCRIPTION  OF  SECTIONS 


43 


Fig.  II 


44 


ICE  RECESSION  IN  NEW  ENGLAND 


i  Fa&srumpsic  c^/q, 


;(;&9r9o/  // 

T,, 1  j  wSBrf 


Kf    I        2       3        4       5 


Fig.  12 


DESCRIPTION  OF  SECTIONS 


45 


MJtES    1  2 

h — r-~'-i r' — r 

KM    t       2       3        4-5 


;^:'n.1:: 


Fig.  13 — Map  showing  the  position  of  the  localities  examined  in  the  Merrimac 
Valley.    Scale  1:160,000. 

Outlines  of  late  glacial  lake  (area  left  white)  and  base  after  C.  H.  Hitchcock  (1878) . 
The  course  of  the  river  has  been  considerably  changed  since  1878. 


46  ICE  RECESSION  IN  NEW  ENGLAND 

Localities  in  the  Hudson  Valley 

On  account  of  a  gap,  comprising  varves  5601  to  5712,  in  the 
normal  curve  in  southernmost  Vermont  and  New  Hampshire, 
the  corresponding  zone  has  been  taken  from  measurements  made 
by  the  writer,  in  192 1,  in  the  Hudson  Valle^^  Since  the  ice 
recession  in  the  Hudson  Valley  is  to  be  treated  by  Baron  De 
Geer,  only  the  necessary'  series  has  been  made  use  of;  and  only 
the  position  of  the  localities  will  be  given  (cf.  PI,  VI). 

a. — Catskill,  N.  Y.,  brickyard  yi  mile  SE  of  the  railroad  station, 
b. — Catskill,  brickyard  a  few  hundred  yards  E  of  the  railroad 

station. 
c. — Hudson,  N.  Y.,  brickyard  a  mile  NE  of  the  railroad  station. 
d. — 5^  rniles  N  of  Hudson,  brickyard  on  the  railroad  \)4.  mile 

N  cf  Stockport. 
e. — Coxsackie,  N.  Y.,  old  brickv^ard  on  the  Hudson  ^  mile  NNW 

of  the  ferr^^ 
f. — wYi  miles  S  of  Albany,  N.  Y.,  the  southernmost  brickyard 

on  the  Hudson,  yi  mile  N  of  Coeymans. 
g. — ^Albany,  brickyard  on  Van  Woert  Street, 
h. — Cohoes,   N.  Y.,  brickyard  on  the  Mohawk  River  at  the 

northwestern  edge  of  the  city, 
i. — 3  miles   NNW  of  Cohoes   (railroad  station),  old  brickyard 

on  the  Mohawk  River  ^  mile  N  of  Crescent  station, 
j. — 4  miles  NW  of  Cohoes,  brickyard  W  of  the  Mohawk  River 

iVa,  miles  NW  of  Crescent  station. 


CHAPTER  IV 
THE  NORMAL  CURVE 

Method  of  Construction 

The  curves  i  to  21  (Pis.  I-V),  form  together  a  normal  curve 
of  4,400  years  which,  with  the  exception  of  a  gap  of  200  to  300 
years  at  Claremont,  N.  H.,  records  the  recession  of  the  last  ice 
sheet  from  Hartford,  Conn.,  to  the  region  of  St.  Johnsbury,  Vt. 
To  construct  it,  all  individual  curves  were  first  matched  and 
corrected  for  numbers  of  varves.  If,  for  example,  out  of  four 
measurements  three  agreed  but  one  had  one  varve  less  or  more 
than  the  others,  the  exact  location  of  the  mistake  was  determined 
and  the  curve  was  corrected  by  dividing  one  varve  in  two  or 
uniting  two  varves  in  one,  so  that  this  curve  agreed  with  the 
three  others.  In  order  to  get  the  number  of  the  varves  accurately, 
as  many  field  measurements  were  made  as  time  and  conditions 
permitted.  Then  the  curves  or  such  parts  of  them  as  included 
undisturbed  varves  of  normal  variation  and  thickness  were 
selected  for  constructing  the  normal  curve.  To  this  end  the 
graphs  were  compared  as  to  thicknesses  of  the  varves  and  as  to 
fluctuations;  and  those  curves  were  discarded  which  showed 
great  difference  in  thickness  from  the  majority  or  poor  agreement 
in  the  shape  of  the  curve.  Having  for  the  greater  part  of  the 
normal  curve  much  material  at  my  disposal,  I  generally  went 
rather  far  in  discrimination,  so  that  except  for  too  thick  or  too 
thin  varves  many  discarded  series  show  excellent  correspondence 
with  the  normal  ones.  The  normal  curve  was  constructed  from 
the  selected  individual  curves  by  calculating  the  average  thick- 
ness of  each  single  varve.  Some  varves,  however,  are  abnormal 
at  all  localities  examined  and  so  have  been  marked  in  the  normal 
curve  by  broken  lines  (cf.  p.  70). 


48  ICE  RECESSION  IN  NEW  ENGLAND 

When  measurements  of  the  same  series  were  at  hand  from 
distant  or  differently  situated  parts  of  the  same  lake  or  from 
separate  valleys,  separate  normal  curves  were  worked  out  for 
each  district  or  valley. 

The  curve  was  drawn  so  that  it  marked  the  actual  thickness 
of  the  varves,  except  when  these  were  too  thick.  The  distance 
between  the  vertical  lines  was  5  millimeters.  In  the  plates  the 
curve  has  been  reduced  one-half.  The  figures  ^,  ^,  etc., 
indicate  the  actual  scale  of  each  part  of  the  graph.  In  order  to 
promote  continued  geochronological  studies,  the  American 
Geographical  Society  is  willing  to  make,  at  cost,  photostat  copies 
on  the  original  scale  of  the  normal  curve  for  anyone  working  on 
the  subject. 

Explanation  of  Symbols  on  Plates  I-V 

In  the  normal  curve  the  large-sized  figures  at  the  arrows 
indicate  the  number  of  measurements  used  in  constructing  the 
curve,  and  the  small-sized  figures  give  the  respective  localities. 
Small-sized  figures  in  parentheses  indicate  profiles  used  for 
control  of  the  number  of  the  varves  but  not  otherwise.  The 
arrows  show  to  what  part  of  the  curve  the  figures  refer. 

No  Connection  As  Yet  With  Absolute  Time 

This  normal  curve  is  not  connected  with  the  chronology  of 
our  time,  and  the  time  elapsed  since  the  ice  sheet  disappeared 
from  New  England  cannot  even  be  estimated  with  any  claim  of 
accuracy.  The  connections  which  De  Geer  (192 1,  p.  70)  supposed 
he  had  made  between  localities  76  and  78  and  the  Swedish  time 
scale  cannot  be  right,  both  because  these  profiles  are  not  charac- 
teristic (cf.  p.  32)  and  because  the  ice  retreat  in  the  respective 
zones  in  New  England  and  Sweden  was  very  different.  The 
series  given  in  De  Geer's  curve,  at  locality  76,  are  7227  to  7297 
and  7338  (?)  to  7368  (?),  and,  at  locality  78,  7159  to  7266  (?). 
These  horizons  essentially  correspond  to  a  halt  and  readvance 
of  the  ice  edge,  while  the  horizons  in  Sweden  with  which  thev 


THE  NORMAL  CURVE  49 

have  been  matched  represent  a  retreat  after  the  long  halt  at 
the  Fenno-Scandian  moraines.  Furthermore,  the  ice  retreat 
in  New  England  does  not  show  agreement  with  that  in  southern 
and  central  Sweden.  Accordingly,  and  because  I  hope  to  be  able 
to  extend  the  curve  southward,  the  lowest  varve  measured  at 
Hartford  has  simply  been  given  the  arbitrary  number  3001. 
The  numbers  of  the  varves  every  ten  years  from  3001  to  7400 
are  marked  on  the  base  lines  of  the  graphs.  For  the  sake  of 
convenience  the  curve  has  been  broken  every  200  years. 

So  far  as  there  is  material  for  it,  then,  the  normal  curve  gives 
the  average  thickness  of  the  annual  clay  layers  during  the 
retreat  of  the  last  ice  sheet  across  the  greater  part  of  New  England. 

Reliability  and  Significance  of  the  Varves  Measured 

In  the  following  the  reliability  of  the  varves  measured,  from 
3001  to  7400,  is  discussed  by  groups  of  varves,  and  comment  is 
made  on  the  agreement  of  curves  covering  the  same  period 
measured  at  different  localities.  Within  a  group  individual 
varves  of  special  significance  are  discussed. 

3001-3449. — ^Very  good.  The  ice  front  was  already  fairly  distant 
when  the  lowest  of  these  varves  were  deposited  in 
the  Hartford  region.  Accordingly,  the  sedimenta- 
tion took  place  under  very  favorable  conditions, 
and  the  varve  curves  from  the  different  localities 
show  a  striking  correspondence.  The  thickest 
varves  are  silty,  and  some  of  them,  as  for  instance 
3444,  perhaps  represent  drainages  of  ice-ponded 
lakes. 
3188  and  3224,  at  locality  5,  contain  quicksand  and 
measure  i}i  and  if^  inches  (3  and  4  cm.)  respec- 
tively.  They  perhaps  mark  drainages. 

3450-3500. — ^The  Hartford  curve  ("3  Conn.,"  PI.  I)  is  good,  while 
the  Springfield  curve  ("3  Mass.")  is  less  reliable, 
since  the  varves  are  often  sandy.  The  correspond- 
ence of  the  two  graphs  is  fairly  good. 


50  ICE  RECESSION  IN  NEW  ENGLAND 

3450-3500. — Continued 

3463  is  remarkably  thick  at  Springfield  and  seems  to 
represent  a  small  drainage  which  made  itself  felt 
only  locally. 

3501-3600. — ^Very  good.  The  Hartford  and  Springfield  curves 
agree  very  well,  considering  the  different  distances 
of  the  sections  from  the  ice  edge  and  the  fact  that 
several  varves,  at  locality  7,  are  sandy. 

3601-3623. — The  two  curves  correspond  well. 

3624-3766. — This  horizon,  at  locality  7,  is  sandy.  The  varves 
are  certainly  not  thick,  and  the  curve  agrees  fairly 
well  with  the  Hartford  curve,  but  it  seems  proper 
to  exclude  the  series  as  not  quite  good. 

The  Hartford  curve  is  good,  though  the  clays 
there  consist  of  very  fine  material,  the  varves  are 
thin,  and  the  varve  limits  sometimes  difficult  to 
distinguish,  since  the  deposition  took  place  very  far 
from  the  ice  border. 

3767-3871. — On  the  whole  the  two  curves  (4-5  Conn.;  4-5  Mass., 
PI.  I)  agree  well,  although  at  Springfield  some 
varves  are  sandy  and  at  Hartford  the  varves  are 
very  thin. 
3820  and  3830,  at  locality  17,  are  sandy  and  each  ^}i 
inches  (10.5  cm.)  thick,  i.e.  several  times  thicker 
than  the  other  varves.  They  mark  drainages. 
3840  and  3866-3870,  at  localities  9  and  17,  are  sandy  and 
probably  represent  drainages. 

3872-4000. — ^Very    good.     The    correspondence    between    the 
different  profiles  is  excellent. 
3931   and   3989  are  silty,   relatively  thick  and  perhaps 

register  drainages. 
3967,  3970,  and  3971,  at  locality  17  only,  are  sandy  and  5, 
3K»  and  2>H  inches  (12.5,  9.5,  and  9  cm.)  thick 
respectively. 

4001-4200. — Good.     The    different    measurements    correspond 
well.     The    varves    show    comparatively    great 


THE  NORMAL  CURVE  51 

400 1  -4200. — Contintied 

variation  in  thickness,  and  several  of  them  are 
unusually  thick;  but  whether  they  are  abnormal  or 
not  cannot  be  determined. 
4003-4012,  at  locality  9,  are  abnormally  thick  and  do  not 
agree  with  those  of  the  other  localities.  The  thickest 
varves,  4004  and  4005,  are  each  4^  inches  (6.7 
cm.).  Varves  4004  and  401 1  are  also  thick  at 
localities  10  and  14. 
4123,  at  localities  10  and  14,  is  silty  to  sandy  and  5  and  7 
inches  (13  and  18  cm.)  respectively. 

4201-4249. — ^The  curve  shows  rather  strong  fluctuations;  but 
whether  the  thick  varves,  which  are  often  sandy, 
are  drainage  varves  or  not  cannot  be  made  out 
with  certainty.  Probably  they  are  normal.  The 
different  measurements  agree  well. 

4250-4330. — Good. 

4331-4338. — ^The  varves,  which  register  a  drainage,  consist  of 
quicksand  and  silt,  and  the  thicknesses  are  of  no 
value. 

4339-4400. — Rather  good. 

4357-4396,  at  locality  15,  consist  of  rather  coarse  sand,  and 
vary  in  thickness  from  2  inches  (5  cm.)  to  5>^  feet 
(1.7  m.).  The  winter  layers  sometimes  were  eroded 
away  during  the  spring  following  their  deposition. 
At  locality  16,  K  mile  (1.2  km.)  to  the  NW,  varves 
4387-4396 — the  varves  below  4387  not  measured — 
are  sandy  but  3  to  1 1  times  thinner  than  those  at 
locality  15.  Varve  4405,  at  both  localities,  begins  a 
long  series  of  thin  varves  (see  p.  15).  The  horizon 
in  question,  at  locality  15,  lies  at  an  elevation  of 
about  150  feet  and,  at  locality  16,  at  a  height  of 
about  100  feet.  The  glacial  lake,  according  to 
Emerson  (1898,  p.  657),  reached  the  level  of  about 
285  feet.  Drainage  and  strong  current  evidently 
played  a  prominent  r6le  in  the  development  of  the 


52  ICE  RECESSION  IN  NEW  ENGLAND 

4339-4400. — Continued 

horizon.  The  difference  between  the  varves  at  the 
two  localities  seems  to  indicate  that  the  water 
depth  influenced  the  sedimentation  and  that  the 
horizon,  at  locality  15,  was  deposited  in  rather  shal- 
low water.  The  case  is  difficult  to  understand  if  the 
water  depths  were  so  great  as  150  feet  at  locality  15 
and  200  at  locality  16.  And  so  it  is  not  unlikely 
that  the  lake  reached  its  highest  level  after  year 
4400  by  the  rising  of  its  outlet  below  Middletown, 
Conn.  (cf.  p.  8).  This  is  also  corroborated  by 
the  fact  that  the  varve  silts  in  the  region  go 
over  into  sand  deep  below  the  highest  level  of  the 
lake,  at  locality  11,  for  instance,  about  150  feet 
below  it. 

4398  is  relatively  much  thicker  at  locality   16  than  at 

locality  15. 

4399  and  4400,  at  localities  15  and  16,  are  sandy  and  record 

a  drainage.  The  thicknesses,  at  locality  15,  are  3>^ 
and  S}i  inches  (9  and  13  cm.)  and  at  locality  16, 
3%  and  25/8  inches  (9.5  and  6.7  cm.). 
4401-4600. — Very  good.  The  agreement  of  the  curves  is  striking 
even  between  such  localities  as  16  and  20,  which 
are  separated  by  the  Holyoke  Range  and  accord- 
ingly were  very  differently  situated  in  relation  to 
the  ice  border. 

4404,  at  localities  15  and  16,  is  sandy  and  measures  4  and 
2^  inches  (10  and  6  cm.)  respectively. 

4410,  at  locality  15,  is  sandy  and  measures  i^  inches 
(4.5  cm.)  and  so  is  abnormally  thick. 

4520-4528,  at  locality  20,  represent  a  weak  drainage  which 
made  itself  felt  only  locally.  The  thickest  varve, 
4522,  is  iK  inches  (4.5  cm.). 

4551  and  4552  are  silty  drainage  layers  at  localities  24  and 
25  only.  They  measure  3  and  i^  inches  (7.5  and 
4.2  cm.)  respectively. 


THE  NORMAL  CURVE  53 

4401-4600. — Continued 

4571  perhaps  represents  a  long  and  warm  summer,  since  it 
is  thick  at  all  localities  measured.  It  is  thickest 
at  locality  22,  where  it  reaches  2>^  inches  (6.5 
cm.). 

4586-4634  at  locality  20,  see  page  79  and  Figure  16. 
4601-4800. — Very  good.  The  ice  front  stood  far  north  of  North- 
ampton, and  the  sedimentation  was  very  uniform. 

4618, 4633, 4661, 4742,  and  4760  are  certainly  conspicuously 
thick  but  may  nevertheless  represent  warm  sum- 
mers. Numbers  4618,  4742,  and  4760  are  silty  in 
the  Northampton  region,  and  4618  as  well  south 
of  Amherst. 

4654,  at  locality  19  only,  represents  an  inconsiderable 
drainage.  It  contains  sand  and  is  1)4  inches 
(3  cm.)  thick. 
4801-5000. — ^Very  good.  The  different  measurements  show 
excellent  agreement.  This  is  the  case  also  with 
the  section  at  locality  18  which  has  mostly  not  been 
used  in  calculating  the  normal  curve,  because  the 
varves  are  considerably  thinner  than  those  at  the 
other  localities. 

4823  and  49 1 1  are  silty  but  probably  represent  warm  sum- 
mers. 
5001-5083. — ^Very  good.  Like  the  varves  under  5000. 
5084-5200. — 'The  agreement  between  the  two  curves  (both 
"11  Mass.,"  PI.  II),  is  good  considering  the  fact 
that  the  upper  curve  is  based  on  measurements  of 
the  proximal  parts  of  the  varves  and  the  lower  one 
on  such  of  the  distal  parts. 

5 1 76-5 1 78,  at  locality  26,  mark  a  drainage.  They  contain 
fine  sand  and  measure  ^}4,  2j4,  and  2^  inches 
(13,  6.8,  and  6.6  cm.)  respectively. 

5184-5200,  at  locality  28,  show  very  great  variations  in 
thickness  from  year  to  year  and  therefore  have 
not  been  used  in  the  normal  curve. 


54  ICE  RECESSION  IN  NEW  ENGLAND 

5084-5200. — Continued 

5192,  at  locality  26,  is  relatively  much  thicker  than  at 
point  28. 
5201-5400. — In  spite  of  several  and  considerable  drainages  the 
curve  from  Greenfield  (upper  "12  Mass.")  shows 
rather  good  correspondence  with  that  from  North- 
ampton (lower  "12  Mass."). 

5201-5253,  at  localities  27  and  28,  show  very  great  fluctua- 
tions, and  some  of  them  are  sandy  and  attain 
considerable  thicknesses.  The  thick  varves  differ 
greatly  at  the  two  localities,  though  these  lie  in 
the  same  valley  and  only  600  yards  apart  (cf. 
varves  5299-5303  and  5307-5313). 

5220-5222,  at  locality  26,  and  varve  5222,  at  localities  27 
and  28,  are  drainage  layers  and  consist  of  fine  sand 
and  silt.  Varve  5222,  at  localities  27  and  28,  is 
g}4  inches  (24  cm.)  thick. 

5245-5249,  at  locality  26,  are  sandy.  At  localities  27  and 
28  they  are  sandy  and  very  thick. 

5253,  at  locality  26,  records  a  drainage. 

5270,  5272,  5277,  5281,  5282,  and  5285,  at  all  localities,  are 
sandy. 

5281,  at  locality  26,  is  4  inches  (10  cm.)  thick  and  represents 
a  drainage. 

5299-5303  and  5307-5313,  at  locality  28,  are  thick  and 
consist  of  coarse  sand;  5310  is  14  inches  (35  cm.). 
At  locality  27  the  same  varves  do  not  exceed  i}4 
inches  (4  cm.)  (see  Fig.  19,  and  p.  69). 

5310  and  531 1,  at  locaHty  26,  are  each  2}^  inches  (6  cm.) 
thick  and  somewhat  sandy. 

5316,  at  locality  28,  measures  4>^  inches  (11.5  cm.). 

5397.  at  locality  26,  is  45^  inches  (10.5  cm.). 
5401-5437. — Good.     The    agreement   between    the    Greenfield 
(upper   "13    Mass.,"   PI.    Ill)    and    Northampton 
(lower  "13  Mass.")  curves  is  very  fine. 


THE  NORMAL  CURVE  55 

540 1  -5437 . — Continued 

5401  and  5403,  at  locality  28,  are  sandy  and  2)4  and  2 

inches  (6  and  5  cm.)  respectively. 
5433    and    5434,   at   localities    26   to   28,  are   somewhat 
sandy. 

5438-5500. — ^The  agreement  among  the  three  curves  (the  same, 
and  "13  N.  H.")  is  very  good  in  view  of  the  dif- 
ferent conditions  under  which  the  clays  were 
deposited  in  the  Greenfield,  Northampton,  and 
Hinsdale  districts.  The  thick  varves,  at  locality  29, 
are  sandy. 
5452,  5457,  and  5495,  at  localities  26  to  28,  are  somewhat 
sandy. 

5501-5600. — Of  the  curves,  one  of  which  is  from  the  Connecticut 
("13  N.  H.")  and  the  other  from  the  Hudson  Valley 
("13  N.  Y."),  neither  is  good.  At  locality  29,  in  the 
Connecticut  Valley,  the  sediments  consist  of  silt 
and  sand  deposited  in  a  very  narrow  lake  with  a 
strong  current.  In  the  Hudson  Valley  the  material 
from  which  the  clay  was  derived  was  so  fine  that 
the  whole  varve  practically  consists  of  fat  clay, 
and  the  varves  consequently  are  difficult  to  dis- 
tinguish. Furthermore,  the  clay  is  often  slidden. 
The  series  5522  to  5537  is  somewhat  uncertain, 
since  the  varve  limits,  in  both  valleys,  are  exceed- 
ingly difficult  to  distinguish.  On  the  whole,  how- 
ever, the  two  curves  agree  well. 

5601-57 12. — Rather  good.    This  series  could  not  be  found  in 
the  Connecticut  Valley.    It  is  therefore  borrowed 
from  measurements  in  the  Hudson  Valley. 
5671-5676  represent  a  very  considerable  drainage  (cf.  p.  99) 

5713-5800.— The  graph  from  the  Hudson  Valley  (14  N.  Y.)  is 
continued  to  show  the  connection  with  the  New 
England  curves  (14  Vt.  and  14  N.  H.).  The  cor- 
respondence among  them  is  rather  good.  Par- 
ticularly interesting  is  the  fact  that  most  of  the 


56  ICE  RECESSION  IN  NEW  ENGLAND 

5713-5800. — Continued 

exceptionally  thick  varves  agree  in  all  three  valleys 
(cf.  p.  54). 

5734,  in  the  Connecticut  and  Merrimac  Valleys,  is  cer- 
tainly much  thicker  than  in  the  Hudson  Valley 
and  perhaps  records  a  drainage,  but  this  is  not 
quite  certain;  it  might  mark  an  unusually  hot 
summer. 

5740,  at  locality  45,  and  5783,  in  the  Hudson  Valley,  are 
abnormally  thick. 
5801-5879.— The  curves  (both  "15  N.  H.,"  and  "15  Vt."),  though 
from  separate  valleys,  correspond  comparatively 
well.  The  agi cement  between  the  two  New  Hamp- 
shire curves  is  good. 

5838  and  5845,  at  locality  49  in  the  Merrimac  Valley, 
measure  2  and  2%  inches  (5  and  7  cm.).  They 
consist  of  coarse  sand  containing  pieces  of  clay. 

5862,  5863,  5870,  5878,  and  5879,  in  the  Connecticut  Valley, 
are  evidently  drainage  varves.  At  locality  34 
varves  5870,  5878,  and  5879  are  respectively  12,  8, 
and  II  inches  (30,  21,  and  28  cm.)  thick. 
5880-6000. — The  correspondence  between  the  Connecticut  and 
the  Merrimac  curves  is  fairly  good. 

5881,  at  locality  49,  measures  4^  inches  (11  cm.).  It 
consists  of  coarse  sand  containing  pieces  of  clay. 

5907,  5916,  5974,  and  5991,  in  the  Connecticut  Valley,  may 
represent  drainages.  Varves  5907  and  5916,  at 
locality  34,  are  7  and  12  inches  (18  and  30  cm.) 
thick  respectively.  At  locality  32,  varves  5973 
and  5974  consist  of  quicksand  and  measure  7  and 
II  inches  (18  and  28  cm.). 

5954  (or  5955  ?)>  at  locality  49,  consists  of  coarse  sand  and 

is  sy^  inches  (13  cm.)  thick. 

6001-6200. — ^The   correspondence   between   the   two   curves   is 

fairly  good.   Varves  6043,  6074,  6137,  and  6168  are 

too  thick  in  the  Connecticut  Valley  (lower  "16  Vt.- 


THE  NORMAL  CURVE  57 

600 1  -62  00 . — Continued 

N.  H.,"  PI.  IV).  On  the  other  hand  a  few  other 
varves  are  somewhat  too  thick  in  the  Merrimac 
Valley  (upper  "16  Vt.-N.  H."),  where  several  of  the 
thickest  layers  are  sandy  or  silty. 

The  majority  of  6010-6082,  at  locality  47,  are 
thick  and  more  or  less  sandy,  probably  mainly 
because  of  the  fact  that  the  late  glacial  Suncook 
River  discharged  into  the  lake  4  miles  to  the 
northeast. 

6037  and  6120,  at  locality  31,  are  i^  and  1%  inches 
(4  and  4.3  cm.)  thick  and  thus  abnormal.  At  lo- 
cality 35  varve  6037  is  somewhat  thinner  than 
varve  6036,  and  varve  6120  is  somewhat  thicker 
than  61 19. 

6074,  at  localities  35  and  40,  measures  I2>^  and  10  inches 
(25  and  32  cm.)  respectively. 

Most  of  the  varves  6 142-6 162,  at  locality  52,  are 
sandy  and  more  or  less  thicker  than  at  the  other 
localities,  probably  because  the  current  swept  over 
the  locality. 

6160,  at  locality  31,  is  abnormal  and  i}4  inches  (4  cm.) 
thick. 

6 1 78-6 1 83,  at  localities  54  and  55,  are  sandy  and  locally  too 
thick  because  of  strong  current. 

6196,  at  locality  54,  is  sandy  and  3^  inches  (8  cm.)  thick, 
while,  at  the  adjacent  point  55,  it  measures  i}i 
inches  (3.3  cm.),  i.e.  is  normal 
6201-6277. — ^The  correspondence  between  the  two  curves  (both 
"17  Vt.-N  .H.")  is  fairly  good.    In  the  Connecticut 
Valley  (lower  curve),  however,  varves  6258  and 
6275,  among  others,  are  sandy  and  too  thick. 
6278-6352. — Fairly  good.   Varve  6308  is  sandy  and  perhaps  of 
abnormal  thickness.    Some  other  varves  also  are 
sandy  because  deposited  in  very  shallow  water. 
6353-6600. — Gap. 


58  ICE  RECESSION  IN  NEW  ENGLAND 

6601-6607. — Sandy  bottom  varves,  somewhat  uncertain. 

6608-6628. — Comparatively  good,  but  sandy. 

6629-6641. — Good,  silty. 

6642-6662. — Good.  The  considerable  thicknesses  of  varves 
6643  and  6646,  at  locality  63,  may  be  due  to  the 
fact  that  they  were  deposited  rather  close  to  the 
ice  edge. 

6663-6800. — Good.  The  different  measurements  correspond  very 
well. 
6687  is  silty  and  remarkably  thick  and  perhaps  represents 

a  drainage. 
6694  is  questionable. 
67 1 2-67 1 5  consist  of  coarse  silt  and,  no  doubt,  mark  a 

drainage. 
6779,  at  locality  65,  contains  sand  and  silt  and  is  2)H  inches 
(9.5  cm.)  thick.   It  may  represent  a  small  drainage. 

6801-6903.— The  curves  (both,  19  "Vt.-N.  H.,"  PI.  V)  are  some- 
what uncertain  both  regarding  thicknesses  and 
number  of  varves.  At  locality  63  the  varves  are 
silty  and  sandy  and  have  thin  winter  layers.  They 
are  thicker  than  at  points  66  and  67.  The  reasons 
for  this  may  be  that  they  were  deposited  in  shallow 
water  and  that  several  side  valleys,  of  which  those 
now  drained  by  the  White  River  and  Mascoma 
River  may  be  mentioned,  join  the  main  valley 
south  of  localities  66  and  67.  The  section  at  locality 
66  is  relatively  good.  At  locality  67  the  varves  are 
wavy  and  have  lenses  of  sand. 
6806-6810  are  drainage  varves.  In  the  curve  the  thick- 
nesses of  the  varves  at  locality  63  are  given. 
Varves  6807  and  6808  consist  of  sand  and  silt.  The 
thicknesses  at  locality  67  are:  1%  inches  (4.5  cm.), 
5  feet  7  inches  (1.7  m.) — 2  feet  2>}^  inches  sand  +  3 
feet  3^  inches  silt  and  clay  (0.7 -j-  i.o  m.) — ; 
ii>^  feet  (3.5  m.) — 4  feet  7  inches  sand  +  6  feet 
II  inches  silt  and  clay  (1.4  m.  }i  2.1  m.) — ;  i  foot 


THE  NORMAL  CURVE  59 

680 1  -6903 . — Continued 

3  inches  (38  cm.) ;  and  i  foot  SH  inches  (45  cm.) 
respectively.  Varve  6806,  accordingly,  does  not 
represent  drainage  at  locality  67. 
6855  is  sandy  and  marks  a  drainage. 
6903  is  relatively  much  thicker  at  point  63  (dashed  line) 
than  at  67  (full  line),  indicating  a  drainage  from  one 
of  the  side  valleys. 

6904-7000.— Fairly  good.  The  two  curves  (both,  "19  Vt.-N.  H.") 
correspond  rather  well. 

At  locality  63  these  varves  are  silty  to  sandy 
with  very  thin  winter  layers.  The  different  meas- 
urements agree  well;  this  horizon  is  much  better 
than  the  series  6801-6903.  Some  varves,  particu- 
larly 6928,  6936,  6937,  and  6946,  are  a  little  too 
thick.  Varve  6997  marks  a  considerable  drainage 
which  originated  above  locality  67. 

In  the  Woodsville  district  (lower  curve)  there 
occurred  two  marked  drainages,  viz.  in  6915- 
6917  and  6941-6944.  The  layers  consist  of  silt. 
Furthermore,  some  varves,  e.  g.  6949  and  6973, 
are  somewhat  too  thick.  The  fact  that  these 
drainages,  as  well  as  that  during  year  7007,  are 
not  recorded  below  locality  68  seems  to  indicate 
that  there  was  here  a  barrier  high  enough  to 
prevent  the  suspended  material  from  getting  across. 

7001-7073. — ^The  correspondence  between  the  two  curves  (both, 
"20  Vt.-N.  H.")  is  not  good.  At  locality  63  the  sedi- 
ments consist  of  silt  to  sand  and  probably  were 
deposited  m  very  shallow  water.  Accordingly  the 
thicknesses  of  the  varves  are  not  reliable.  The 
lower  curve,  based  on  the  measurements  in  the 
Woodsville  district,  except  for  some  drainages,  is 
good.  The  different  measurements  show  good 
agreement. 
7007  is  sandy  and,  at  localities  79,  80,  and  82,  measures 


60  ICE  RECESSION  IN  NEW  ENGLAND 

7001-7073. — Continued 

SHi  I3»  and  6  inches  (13,  33,  and  15  cm.).  At 
the  localities  south  of  Woodsville  this  varve  is 
everywhere  questionable  because  of  sliding.  Judg- 
ing from  the  thicknesses  the  drainage  reached  the 
lake  in  the  vicinity  of  locality  80. 

7020,  in  the  lake  at  Woodsville,  is  silty  and  too  thick. 

7028,  at  localities  79,  70,  73,  and  other  points  south  of 
79,  is  silty  and  about  2  inches  (5  cm.)  thick,  while, 
at  localities  80  and  82,  it  measures  i  and  i)4  inches 
(2.6  and  3.2  cm.)  respectively,  showing  that  the 
drainage  originated  from  one  of  the  side  valleys 
at  Woodsville.  Since  this  varve,  at  locality  76, 
is  only  ^  inch  (2  cm.)  thick,  it  probably  marks 
a  small  drainage  through  the  Ammonoosuc  River. 

7060-7065  are  silty  and  somewhat  doubtful. 
7074-7200. — Rather  good.  The  horizon,  at  most  localities,  is 
exceedingly  fat,  almost  like  green  soap.  Conse- 
quently the  thicknesses  of  the  varves  are  often 
altered  by  pressure  from  overlying  strata.  This 
may  be  the  reason  why  the  correspondence  among 
the  different  measurements,  though  fair,  is  not  so 
good  as  might  be  expected.  On  account  of  the 
consistency  of  the  clay,  slides  occur  frequently. 

7172-718 1  are  more  accentuated  at  locality  82  and  at 
Inwood  than  at  the  other  localities,  but  even  at 
Inwood  two-thirds  to  three-quarters  of  the  varves 
consist  of  greasy  clay, 

7200,  at  locality  72,  measures  2}i  inches  (5.5  cm.);  at  73, 
2,H  inches  (9.5  cm.) ;  at  74,  2  inches  (5  cm.) ;  at  77. 
i^  inches  (3.5  cm.);  at  79,  4^  inches  (11  cm.); 
at  80,  10  inches  (25  cm.);  at  81,  SJ4  inches  (21 
cm.);  at  82,  I2>^  inches  (32  cm.):  at  90,  15^ 
inches  (40  cm.);  and  at  91,  4^  inches  (12  cm.). 
At  localities.  72  to  79  it  is  silty,  at  91  sandy  and 
silty,  and  at  the  rest  sandy.   It  evidently  represents 


THE  NORMAL  CURVE  6i 

7074-720C. — Continued 

a  drainage  into  the  Connecticut  above  its  junction 

with  the  Passumpsic  (cf.  p.  70). 
7201-7357. — ^Very  good  except  for  some  drainages.  The  different 

measurements     correspond     very     well.      Besides 

varves  mentioned  below  some  others,  like  7254  and 

7274,  are  somewhat  doubtful. 
7201    (together   with    7200)    represents    a    drainage.     It 

measures,  at  locality  72,  i  inch  (2.5  cm.);  at  73, 

lyi  inches  (2.8  cm.);  at  77,  %  inch  (2  cm.);  at  78, 

1  inch  (2.6  cm.);  at  79,  i^  inches  (3.5  cm.);  at  80, 

2  inches  (5  cm.);  at  82,  4  inches  (10  cm.);  at  90, 
5^  inches  (13.5  cm.);  and  at  91,  1%  inches  (4.5 
cm.)  (cf.  p.  70). 

7203  marks  a  drainage.  The  thickness,  at  locality  72,  is 
2yi  inches  (5.3  cm.);  at  73,  2^  inches  (7  cm.);  at 
77,  1%  inches  (3  cm.);  at  79,  4  inches  (10  cm.); 
at  80,  3>^  inches  (8  cm.);  at  81,  6  inches  (15  cm.); 
at  82,  8>^  inches  (21  cm.);  at  90,  13^^  inches 
(35  cm.) ;  and  at  91,  4  inches  (10  cm.).  At  localities 
72  to  77  it  consists  of  silt,  at  91  of  silt  and  fine  sand, 
and  at  the  other  points  of  fine  sand.  It  may 
represent  a  drainage  into  the  Connecticut  NE  of 
its  junction  with  the  Passumpsic  (cf.  p.  70). 

7213,  at  locality  73,  measures  7  inches  (17.5  cm.);  at  JJ, 
3^  inches  (8.5  cm.) ;  at  79,  8  inches  (20  cm.) ;  at  82, 
235^  inches  (60  cm.) — 15%  inches  (40  cm.)  sand 
+  8  inches  (20  cm.)  silt  and  clay — ;  at  83,  35>^ 
inches  (90  cm.) — 23^^  inches  (60  cm.)  fine  sand 
and  silt  +  12  inches  (30  cm.)  clay — ;  at  90,  27^^ 
inches  (70  cm.);  and  at  91,  '&%  inches  (21  cm.). 
The  varve  consists,  at  73  and  77,  of  silt;  at  79  and 
90,  of  fine  sand;  and,  at  91,  of  fine  sand  and  silt. 
Together  with  varve  7214  it  records  a  drainage  into 
the  Connecticut  above  its  junction  with  the  Pas- 
sumpsic (cf.  p.  70). 


62  ICE  RECESSION  IN  NEW  ENGLAND 

7201-7357. — Continued 

7214,  at  locality  73,  measures  i)4  inches  (3  cm.);  at  79, 
I  inch  (2.5  cm.);  at  82,  2  inches  (5.3  cm.);  at  83, 
2}i  inches  (6.8  cm.);  at  90,  2%  inches  (7  cm.); 
and  at  91,  2  inches  (5  cm.). 

7225,  at  localities  82,  83,  and  86,  is  sandy  and  abnormally 
thick.  It  measures  2}4,  4,  and  2  inches  (6.5,  10, 
and  5  cm.)  respectively. 

7228-7230,  at  localities  82,  83,  86,  89,  and  90,  are  silty 
to  sandy  and  abnormally  thick.  They,  at  locality 
86,  measure  4,  3>^,  and  2^  inches  (10,  8,  6  cm.) 
respectively.  Inasmuch  as  they  are  thinner  at  91, 
they  evidently  mark  a  drainage  into  the  Connecti- 
cut. Down  the  valley,  at  locality  73,  this  drainage 
was  hardly  felt. 

7237,  at  locality  73,  measures  ^  inch  (i  cm.);  at  79, 
^  inch  (1.5  cm.);  at  82,  2  inches  (5.3  cm.);  at  86, 
3>^  inches  (9  cm.) ;  at  89,  2^  inches  (6  cm.) ,  at  90, 
2}4  inches  (6.5  cm.);  and,  at  91,  J4  inch  (2.3  cm.). 
It  is,  at  locality  86,  sandy,  but  elsewhere  silty  or 
clayey. 

7295,  at  locality  73,  measures  %  inch  (2  cm.) ;  at  82,  2>}i 
inches  (8  cm.);  at  84,  ^yi  inches  (13  cm.);  at  86, 
3^  inches  (8.5  cm.);  at  88,  2  inches  (5.3  cm.); 
at  89,  2}4  inches  (5.8  cm.) ;  at  91,  i}i  inches  (3  cm.). 
It  is  sandy  at  localities  82,  86,  88,  and  89. 

7296  and  7297  are  abnormally  thick  at  localities  86  and  89. 

7304  and  7305,  at  locality  73,  measure  J4  and  i  inch  (2.3  and 
2.4  cm.) ;  at  82,  2%  and  sH  inches  (7  and  14  cm.) ; 
at  83,  4  and  igJ/2  inches  (10  and  50  cm.) ;  at  84,  7% 
and  12  inches  (19.5  and  31  cm.);  at  86,  sH  and 
ioJ>4  inches  (13  and  27  cm.) ;  at  88,  3  and  s}i  inches 
(7.8  and  13  cm.);  at  91,  i}i  and  1^2  inches  (2.8 
and  4  cm.).  At  locality  84  the  varves  consist  of 
quicksand,  at  83  and  86,  of  sand  and  silt,  and 
elsewhere  of  silt. 


THE  NORMAL  CURVE  63 

7201-7357. — Continued 

7307,  at  locality  73,  measures  ^  inch  (i  cm.);  at  82,  i^ 
inches  (3.5  cm.);  at  84,  2}4  inches  (6.5  cm.);  at  85, 
27>^  inches  (70  cm.);  at  86,  2}4  inches  (6.5  cm.); 
at  88,  2  inches  (5  cm.);  at  89,  2^^  inches  (6  cm.); 
at  91,  J4>  inch  C2.3  cm.).  At  localities  84  and  85 
the  varve  consists  of  quicksand  and  coarse  sand 
respectively,  at  86  of  sand  and  silt,  and  at  the 
other  localities  of  silt  and  clay. 

7314,  at  locality  73,  measures  ^^  inch  (i  cm.);  at  82,  ^yH 
inches  (9  cm.) ;  at  83,  io><  inches  (26  cm.) ;  at  84, 
^yi  inches  (13  cm.) ;  at  85,  sH  inches  (14  cm.) ;  at 
86,  4>^  inches  (10.5  cm.);  and  at  88  and  89,  2>H 
inches  (8.5  cm.).  At  locality  85  it  consists  largely 
of  sand,  at  83,  84,  86,  and  88  of  sand  and  silt,  and 
at  the  other  points  of  silt  and  clay. 
7358-7400- — Somewhat  uncertain  because  the  varve  limits  are 
very  difhcult  to  distinguish. 

7399  begins  a  series  of  comparatively  thick  varves  con- 
sisting of  exceedingly  greasy  clay. 


CHAPTER  V 
THE  CONNECTIONS 

The  connections  of  varve  curves,  as  explained  on  page  4,  are 
based  on  agreement  among  them.  Accordingly,  it  is  after  all 
a  matter  of  personal  judgment  whether  connection  is  found  or 
not.  The  personal  factor,  however,  can  be  practically  eliminated 
by  only  accepting  fine  and  persistent  agreement  among  relia- 
ble graphs.  The  greater  the  number  of  graphs  which  are  found 
to  agree,  the  more  certain  is  the  connection.  Since  the  clay 
sedimentation,  i.  e.  the  curves,  reflects  the  climatic  fluctuations, 
and  since  these  are  periodical,  characteristic  features  in  the 
graphs  often  recur  somewhat  different  or  exactly  similar.  But 
the  correspondence,  as  a  rule,  persists  only  for  a  small  group  of 
varves,  so  that  if  the  profiles  are  not  too  short  the  danger  of  mis- 
connection  is  avoided. 


Value  of  Varves  for  Study  According  to 
Their  Characteristics 

The  value  of  the  varve  clays  for  chronological  studies  varies 
greatly.  The  best  varves  are  one  to  two  inches  thick  and  consist 
of  a  silty,  light-colored  summer  layer  and  a  greasy,  dark  winter 
layer.  They  are  easy  to  measure  and  give  the  most  typical 
curve.  Thick  varves  are  generally  good,  so  long  as  they  do  not 
contain  coarser  material  than  silt,  but  they  show  sometimes  too 
great  annual  fluctuations.  When  they  contain  sand,  they  are 
not  reliable,  since  they  then  are  often  entirely  too  thick  and 
always  show  exaggerated  variations  from  year  to  year.  Such 
varves  indicate  drainage  of  ice-ponded  lakes  or  deposition  close 
to  the  ice  edge  or  in  strong  current  or  in  too  shallow  water.  Very 
thin  varves,  besides  being  difficult  to  measure,  give  a  curve  which 


THE  CONNECTIONS  65 

is  too  flat  and  uncharacteristic  for  sure  connections.  Very  fat 
clay  requires  great  caution.  A  section  may  look  perfect,  but 
nevertheless  be  valueless.  At  locality  78  measurements  a  few 
yards  apart,  of  apparently  good  series,  showed  more  disagreement 
than  correspondence,  because  the  clay,  which  resembles  green 
soap  in  consistency,  had  been  compressed.  Another  danger  is 
that  series  of  varves  of  such  clay  can  have  slidden  away  with- 
out leaving  any  trace,  even  in  a  long  clean  section.  However, 
by  controlling  the  measurements  with  those  made  at  other 
localities  mistakes  can  be  avoided. 


Abundance  and  Quality  of  New  England  Material 

The  deposition  of  varve  clay  in  New  England  occurred  under 
very  favorable  conditions.  The  varves  are,  as  a  rule,  very  well 
developed  and  of  good  thickness,  and  the  series  show  good  cor- 
respondences almost  without  exception.  Very  often  the  agree- 
ment is  quite  striking.  The  large  amount  of  material  at  my  dis- 
posal has  made  it  possible  to  control  the  measurements  varve  by 
varve  and  to  discard  poor  material,  as  explained  on  page  47. 
Often  the  connections,  based  on  agreeing  curves,  are  supported 
by  such  peculiarities  as  drainage  varves  and  changes  in  con- 
sistency and  color  of  the  clay. 

Examples  of  Individual  Curves  to  Illustrate 
Agreement  Among  Them 

At  the  bottom  of  Plate  V,  parts  of  original  curves  are  repro- 
duced so  as  to  give  some  illustration  of  their  correspondence  with 
one  another.  There  are  three  groups  of  curves,  the  first  com- 
prising localities  i  and  4  (box  I),  the  second  localities  15,  18, 
and  24  (box  II),  and  the  third  localities  82,  90,  and  91   (box 

HI). 

Localities  i  and  4  lie  6.4  miles  (10.4  km.)  apart,  the  latter  that 
much  closer  to  the  ice  edge  (Fig.  5).  No  alterations  whatever  of 
the  graphs  have  been  made,  since  the  original  measurements 


66  ICE  RECESSION  IN  NEW  ENGLAND 

were  correct,  as  is  proved  by  their  agreement  with  several  other 
profiles  (see  PI.  I).  The  correspondence  of  the  two  graphs  is 
excellent. 

Localities  15,  18,  and  24  lie  at  the  following  distances  from 
each  other:  15  and  18,  3.7  miles  (6  km.),  15  and  24,  8.3  miles 
(13.5  km.);  18  and  24,  9.7  miles  (15.7  km.).  Localities  18  and 
24  are  situated  in  the  same  glacial  lake,  though  on  different 
sides  of  it,  and  locality  15  in  a  lake  separated  from  the  former  by 
the  Holyoke  Range,  except  for  one  or  two  narrow  gaps  (Fig.  6). 
Since  most  of  the  material  coming  from  the  melting  land  ice  was 
deposited  in  the  nearer,  or  Northampton,  lake,  the  varves  at 
localities  18  and  24  are  thicker  than  those  at  locality  15.  Varves 
4551  and  4552,  at  locality  24,  mark  an  inconsiderable  drainage 
not  felt  outside  the  bay  southeast  of  Amherst.  The  curves  with 
two  exceptions  are  reproduced  exactly  as  measured  in  the  field. 
At  locality  15  the  varves  4553  and  4554  were  incorrectly  meas- 
ured as  one,  and  at  18  varve  4531  was  divided  in  two.  In  the 
first  case,  the  supposed  varve  has  been  divided  so  as  to  match 
those  at  the  other  localities,  and  in  the  latter  case  the  two  varves 
have  been  united.  These  varves  have  been  marked  by  dotted 
lines.  Considering  the  different  position  of  the  localities  in  rela- 
tion to  the  ice  border,  the  agreement  among  the  three  curves  is 
remarkable. 

The  third  group  comprises  localities  82,  90,  and  91.  The  dis- 
tance from  82  to  90  is  8.4  miles  (14.5  km.) ;  from  90  to  91,  3  miles 
(4.8  km.).  All  three  lie  in  the  same  glacial  lake,  but  locality  91 
in  a  narrow  branch  now  constituting  the  Passumpsic  valley, 
locality  90  in  the  same  branch  less  than  a  mile  north  of  its  junc- 
tion with  the  Connecticut,  and  82  farther  south  in  the  lake  (Fig. 
12).  Varves  7200  and  7201  are  sandy  and  silty  and  mark  a 
drainage.  Since  they  are  much  thinner  at  locality  91  than  at 
the  two  other  points,  the  drainage  evidently  came  into  the 
Connecticut  above  its  junction  with  the  Passumpsic.  The  graphs 
show .  the  original  measurements  unchanged,  except  for  two 
cases  in  curve  82,  which  have  been  marked  by  dotted  lines. 
Varves  71 16  and  71 17  had  been  incorrectly  measured  as  one, 


THE  CONNECTIONS  67 

and  number  7156  had  been  divided  in  two.   The  correspondence 
among  the  three  curves  is  excellent. 


Agreement  Among  Curves  from  Widely  Separated 
Localities 

The  agreement  between  calculated  normal  curves  from  differ- 
ent parts  of  the  same  lake,  or  from  widely  separated  valleys, 
can  be  studied  on  the  plates.  For  details  regarding  these  curves 
reference  may  be  made  to  the  description  on  pages  49-63. 
Curves  3  to  5  (PI.  I)  show  the  striking  agreement  between 
normal  curves  based  on  two  groups  of  measurements  in  the  same 
lake,  one  group  lying  20  miles  (32  km.)  closer  to  the  ice  edge  than 
the  other.  Curves  11,  12,  and  13  (Pis.  II  and  III)  are  constructed 
from  profiles  in  a  corresponding  situation  to  the  ice  border  as 
those  just  mentioned.  The  latter  part  of  graph  13  represents 
measurements  in  the  Hudson  and  Connecticut  Valleys,  and  curve 

14  (PI.  Ill)  records  profiles  in  the  Hudson,  Connecticut,  and 
Merrimac  Valleys.  The  distance  between  the  Hudson  and 
Connecticut  Valleys  is  60  miles  (95  km.),  between  the  Connecti- 
cut and  Merrimac  Valleys  50  (80  km.),  and  between  the  Hudson 
and  Merrimac  consequently  no  miles  (175  km.).  The  cor- 
respondences between  the  curves  are  on  the  whole  good,  and  in 
some  horizons  excellent,  considering  the  great  distances  between 
these  lakes  and  the  differences  in  their  drainage  areas.  The 
series  from  the  Hudson  Valley  is  put  in  to  fill  a  gap  in  the  Con- 
necticut curve,  but  only  so  much  is  reproduced  as  is  necessary 
to  show  connections.  As  a  matter  of  fact,  the  total  series  extends 
200  varves  downward  and  100  varves  upward,  making  in  all 
600  layers.  The  whole  series  shows  good  agreement  with  the 
Connecticut  and  Merrimac  curves. 

Curves  15,  16,  and  17  (Pis.  Ill  and  IV)  are  based  on  measure- 
ments in  the  Connecticut  and  Merrimac  Valleys,  and  curve 

15  also  on  one  in  the  glacial  lake  at  Keene,  N.  H.  Except  for 
drainage  varves  the  agreement  is  very  satisfactory.  Curves  19 
and  20  (PI.  V),  finally,  are  compiled  from  two  groups  of  measure- 


68  ICE  RECESSION  IN  NEW  ENGLAND 

ments  made  in  probably  different  lakes  (cf.  p.  59)  in  the  Con- 
necticut Valley  50  miles  (80  km.)  apart.  Since  the  lower  lake 
was  supplied  with  masses  of  material  from  its  side  valleys, 
principally  from  the  White  River  valley,  the  varves  at  the 
southern  locality,  number  63,  are  three  or  four  times  as  thick 
as  those  in  the  Woodsville  region.  Taking  this  peculiarity  into 
account,  the  correspondence  between  the  curves  is  good. 

Sure  connections  have  accordingly  been  found  across  New 
England  between  points  at  distances  up  to  no  miles  (175  km.) — 
the  most  widely  separated  measurements  of  the  same  horizons 
that  have  been  made.  This  shows  that  the  essentials  for  getting 
connections  are  selection  of  fine  and  undisturbed  series  and 
accuracy  in  measurement.  Then  correct  connections  can  be 
found  irrespective  of  the  distances,  so  long  as  we  keep  within  an 
area  which  was  climatologically  uniform  during  the  ice  retreat, 
and  provided  also  the  local  conditions  were  not  extreme. 


CHAPTER  VI 

ABNORMAL  VARVES,  AND  DISTURBANCES  IN  THE 

CLAY 

Abnormally  Thick  Varves 

Now  and  then  single  varves  or  groups  of  them  are  abnormally 
thick  and  consist  of  silt  or  sand  covered  by  the  usual  thin  clay 
layer.  Such  varves,  as  a  rule,  do  not  reflect  the  climatic  condi- 
tions— the  amount  of  melting — and  in  other  lakes  are  usually 
matched  by  varves  of  normal  thickness.  Thick  varves  can  be 
due  to  different  causes.  Some  of  them  were  caused  by  a  strong 
current  which  for  a  number  of  years  swept  over  the  locality, 
depositing  silt  and  sand,  and  then  shifted  its  course  (cf.  Fig.  19 
and  pp.  51,  54,  57,  82).  The  cause  of  other  abnormally  thick 
varves  lies  in  an  increase  of  the  drainage  area  by  the  uncovering 
of  a  wider  part  of  the  main  valley  or  of  extensive  tributary  val- 
leys (cf.  p.  82).  In  still  other  cases,  deposition  of  thick  varves 
was  due  to  shallowing  of  the  water  as  the  lakes  filled  up  with 
sediments  or  drained  out.  The  depth  of  water  at  which  deposi- 
tion of  abnormal  varves  begins  varied,  of  course,  according  to 
the  situation  of  the  locality,  the  size  of  the  lake,  and  the  amount 
of  water  passing  through  it.  In  the  lake  at  Concord,  N.  H.,  as 
explained  on  page  82,  the  critical  depth  at  some  points  was 
reached  as  much  as  100  feet  beneath  the  level  of  the  lake,  while 
in  quiet  bays  clay  sedimentation  went  on  until  the  bottom  was 
built  up  to  within  15  or  20  feet  of  the  lake  level  (cf.  localities 
57  and  46). 

Drainage  Varves 

Most  interesting  are  those  abnormal  silty  and  sandy  varves 
which  represent  drainages  of  lakes  that  were  ponded  between 
the  ice  edge  and  higher  land,  or  by  dams  of  glacial  deposits. 


70  ICE  RECESSION  IN  NEW  ENGLAND 

The  extra  material  in  the  varves  was  picked  up  by  the  vigorous 
drainage  river  along  its  course.  Drainages  observed  in  the  clay 
deposits  in  New  England  amount  to  more  than  half  a  hundred. 
They  are  rare  in  the  southern  part,  but  numerous  from  northern 
Massachusetts  northward,  where  the  relief  becomes  stronger. 
All  drainage  varves  found  are  treated  under  the  description  of 
the  normal  curve  on  pages  49-63.  Although  it  is  desirable  to 
get  rid  of  them  in  the  normal  curve,  the  attempt  to  do  this  has 
not  always  succeeded.  To  distinguish  them  they  have  been 
marked  by  dashed  lines.  What  follows  here  is  only  a  general 
account. 

While  the  thickest  drainage  varve  observed,  varve  6808,  at 
locality  67,  Hanover,  N.  H.,  is  12  feet  (3.5  m.),  many  of  them 
are  so  thin  that  they  are  not  suspected  to  be  abnormal  before 
they  are  found  to  correspond  to  thin  varves  in  other  valleys. 
This  source  of  mistakes  must  be  kept  in  mind  when  using  the 
varve  curve  as  a  thermograph  and  makes  measurements  in  dif- 
ferent lakes  the  more  desirable. 

Most  drainages  were  inconsiderable  and  took  place  during  a 
single  year.  A  great  many  of  them,  however,  occurred  during  a 
number  of  summers,  though  generally  less  than  five.  Drainages 
of  two  and  three  years  are  common.  In  those  lasting  two  years 
the  amount  of  sediment  brought  during  the  first  year  was  in 
most  cases  the  greater.  In  drainages  continuing  for  three  or 
more  summers  the  amount  of  sedimentation  usually  increased 
during  the  first  one  or  two  years,  reaching  a  maximum  at  or 
before  the  middle  of  the  period  of  drainage.  Occasionally  the 
first  or  the  last  drainage  varve  is  the  thickest. 

Since  the  drainage  layers  grew  in  thickness  towards  the  mouth 
of  the  river  by  which  the  ponded  lake  discharged,  the  position  of 
this  lake  can  be  traced  by  their  help.  While  so  far  no  detailed 
studies  have  been  carried  out  to  determine  the  exact  position 
of  ice  lakes,  the  valleys  in  which  they  were  ponded  or  through 
which  the  discharge  took  place  are  in  several  cases  known.  Thus 
Figure  14  shows  three  drainages  which  apparently  came  into  the 
Connecticut  above  its  junction  with  the  Passumpsic,  since  the 


ABNORMAL  VARVES 


71 


Fig.  14 — Curves  showing  three  drainages,  into  the  Connecticut  River  above  its 
junction  with  the  Passumpsic,  of  ice-ponded  lakes  on  the  northwestern  slopes  of  the 
White  Mountains. 


72  ICE  RECESSION  IN  NEW  ENGLAND 

varves  are  comparatively  thin  at  locality  91,  3>^  miles  up  the 
Passumpsic  valley.  The  lakes  had  probably  been  dammed  on 
the  northwestern  slopes  of  the  White  Mountains.  Varve  6997 
(normal  curve  19,  PI.  V)  offers  another  interesting  case.  The 
varve,  at  localities  67  and  63,  marks  a  great  drainage,  measuring 
16  and  14  inches  (40.5  and  35.5  cm.),  but  is  normal  from  locality 
68  northward,  showing  that  the  drainage  originated  south  of 
this.  Since  the  ice  edge  by  this  time  had  retired  far  beyond 
Woods ville,  the  lake  in  question  must  have  been  ponded  by 
glacial  drift. 

Thick  Varves  as  Indications  of  Warm  Summers 

Some  unusually  thick  varves  seem  to  be  a  true  expression  of 
the  amount  of  melting  and  probably  represent  very  long  and 
warm  summers.  They  illustrate  the  necessity  of  having  measure- 
ments from  diiTerent  valleys  in  order  to  understand  the  meaning 
of  many  varves  and  also  show  that,  in  our  caution  not  to  assume 
too  great  climatic  fluctuations,  we  may  easily  go  too  far  (cf.  p.  56). 

Disturbances  in  the  Clay 

Such  disturbances  in  the  clay  as  folded  and  squeezed  zones 
and  faults  are  essentially  of  negative  scientific  interest,  because 
they  prevent  positive  observations.  They  can  have  been  caused 
by  sliding  of  the  clay,  grounding  of  icebergs,  readvancing  of  the 
ice  sheet,  melting  of  buried  ice,  sliding  or  washing  down  of 
rock  or  soil  from  a  hillside,  pressure  due  to  the  weight  of  accu- 
mulated strata,  etc. 

Disturbances  caused  by  sliding  are  frequent  in  regions  where 
the  clay  is  fat  and  where  it  rests  on  an  uneven  surface.  Sometimes 
the  whole  clay  deposit  has  slidden.  In  other  cases  a  few  varves, 
which  formed  a  shearing  plane,  are  crumpled  up  so  as  to  appear 
homogeneous,  while  the  zones  below  and  above  are  undisturbed. 
Such  contorted  zones,  one-half  to  one  foot  thick,  can  often  be 
traced  continuously  through  long  exposures.  In  greasy  clays 
slides  can  occur  even  if  the  dip  of  the  strata  is  slight. 


ABNORMAL  VARVES  73 

Disturbances  due  to  grounding  of  icebergs  are  usually  quite 
local,  even  if  a  great  number  of  varves  may  have  been  involved. 
Sometimes,  however,  icebergs  may  have  given  impulse  to 
extensive  slides. 

Dislocations  due  to  a  readvancing  of  the  ice  sheet  were  more 
extensive  and  thorough.  The  ice  jammed  the  clay  beds  together, 
overturned  clay  blocks,  folded  the  layers,  and  kneaded  sand  and 
till  into  the  clay. 

Faults  in  the  clay  seem  generally  to  have  been  caused  by 
settling  due  to  melting  away  of  icebergs  which,  overloaded  with 
material,  had  sunk  to  the  lake  bottom  and  had  become  buried 
in  the  sediments. 

Disturbances  caused  by  pressure  of  the  clay  itself  or  by  the 
weight  of  overlying  strata  are  most  likely  to  occur  in  very  fat 
clay  or  quicksand.  They  are  treacherous  and  can  sometimes 
be  detected  only  by  comparison  of  different  measurements. 


CHAPTER  VII 

THE    RATE    OF    RECESSION    AND    CONDITIONS 
CONTROLLING  RECESSION 

On  account  of  the  very  considerable  depth  of  the  varve 
sediments  in  the  New  England  valleys  their  bottoms  have  been 
reached  only  at  a  limited  number  of  localities,  almost  all  of 
which  are  situated  in  New  Hampshire  and  Vermont.  Here  the 
rate  of  retreat,  accordingly,  has  been  exactly  determined  in 
several  instances,  while  that  has  not  been  possible  in  Connecticut 
and  Massachusetts.  However,  the  bottom  of  the  clay  has  in 
many  cases  been  almost  reached,  enabling  an  approximate 
determination  of  the  speed  of  the  retreat. 

On  the  map,  Plate  VI,  the  positions  of  the  ice  edge  have  been 
marked  for  every  lOO  years.  Which  of  these  positions  are  deter- 
mined by  bottom  varves  may  be  deduced  from  their  location  with 
reference  to  the  localities  indicated  in  Chapter  III  at  which 
bottom  varves  were  reached.  Accelerated  retreat  between  two 
points  indicated  by  the  speed  south  and  north  of  them  has  been 
shown  on  the  map  by  putting  the  i  co-year  lines  at  different 
distances,  so  as  to  illustrate  as  truly  as  possible  the  gradual 
increase.  Retardation  in  the  recession  has  been  marked  in  a 
corresponding  way. 

The  extent  of  the  examined  field,  which  reaches  from  Hartford, 
Conn.,  to  St.  Johnsbury,  Vt.,  is  185  miles  (298  kilometers). 
The  retreat  across  this  belt  is  registered  by  a  continuous  series 
of  annual  clay  layers  except  for  a  narrow  gap  at  Claremont,  N.  H., 
probably  representing  200  to  300  years.  The  time  occupied  by 
the  recession  from  Hartford  to  St.  Johnsbury  was  about  4,100 
years.  This  makes  an  average  rate  of  22  years  to  a  mile,  or  of 
238  feet  (73  meters)  a  year. 

The  following  table  gives  the  rate  of  retreat  of  the  ice  border 


RATE  OF  RECESSION 


75 


between   the   points   indicated.    The   distances   are   measured 
parallel  to  the  direction  of  the  ice  movement. 

Table  I — Rate  of  Retreat  of  the  Ice  Border 


Time  of  Re- 

Rate of 

Localities 

Distance 

treat  IN 

Retreat   a 

Years 

Year 

I  to  7 

24.2  miles 

=  127,776  feet 

About  525 

243  feet 

None  with  bottom 

38.9  km. 

74  m. 

7  to  17 

5.2  miles 

=  27,456  feet 

About  330 

83  feet 

None  with  bottom 

8.4  km. 

26  m. 

7  to  24 

19  miles 

=  100,320  feet 

>  1,000 

<ioo  feet 

24  with  bottom 

31  km. 

<3i  m. 

7  to  28 

35. 8  miles 

=  189,024  feet 

About  1,630 

116  feet 

None  with  bottom 

57.6  km. 

35  m. 

24  to  28 

16.8  miles 
27.1  km. 

=  88,704  feet 

About  270 

328  feet 
100  m. 

28  to  29 

12.8  miles 

=  67,584  feet 

About  350 

193  feet 

None  with  bottom 

20.8  km. 

59  m. 

29  to  31 

12.4  miles 

=  65,472  feet 

About  275 

238  feet 

None  with  bottom 

20.1  km. 

73  m. 

31  to  40 

19.5  miles 

=  102,960  feet 

>300 

<343  feet 

40  with  bottom 

31.4  km. 

<io5  m. 

45  to  59 

15.2  miles 

=  80,256  feet 

About  275 

292  feet 

Bottom  almost 

24.4  km. 

89  m. 

reached  at  both 

59  to  60 

7.2  miles 

=  38,016  feet 

<I73 

>220  feet 

Depth  to  bottom 

II. 6  km. 

>67  m. 

at  60  unknown 

76 


ICE  RECESSION  IN  NEW  ENGLAND 


Table  I — Rate  of  Retreat  of  the  Ice  Border — Continued 


Time  of  Re- 

Rate of 

Localities 

Distance 

treat  IN 

Retreat    a 

Years 

Year 

6i  to  64 

15.5  miles  =  81,840  feet 

133 

615  feet 

Both  with  bottom 

25  km. 

188  m. 

64  to  67 

4  miles  =  21,120  feet 

<26 

>8i2  feet 

67  practically  with 

6.4  km. 

>246  m. 

bottom 

67  to  70 

21  miles  =  110,880  feet 

>i4i 

<786  feet 

Both  practically 

33.8  km. 

<240  m. 

with  bottom 

70  to  71 

J4  mile  =  2,640  feet 

3 

880  feet 

71  with  bottom 

0.8  km. 

268  m. 

70  to  75 

6  miles  =  31,680  feet 

29 

1092  feet 

75  with  bottom 

9.7  km. 

333  m. 

75  to  79 

5  miles  =  26,400  feet 

24 

II 00  feet 

Both  with  bottom 

8  km. 

335  m. 

79  to  86 

II  miles      =  58,080  feet 

About  70 

830  feet 

86  practically  with 

17.7  km. 

253  m. 

bottom 

Rate  of  Recession  in  the  Southern  Zone 

In  the  southernmost  zone,  between  Hartford  and  Springfield, 
the  recession  was  consequently  rather  fast,  amounting  to  about 
243  feet  (74  m.)  a  year.  In  Massachusetts  the  rate  decreased 
considerably,  averaging  between  Springfield  and  Greenfield  only 
116  feet  (35  m.)  annually.  The  recession,  however,  seems  to 
have  varied  greatly  in  speed  in  different  zones  and  even  to  have 
been  interrupted  by  readvances.  Between  localities  7  and  24  the 
retreat  was  less  than  100  feet  (31  m.)  a  year. 


RATE  OF  RECESSION 


77 


Probable  Oscillations  of  the  Ice  Border  in  the 
Amherst-Northampton  Region 

In  November,  192 1,  there  was,  at  locality  24,  southeast  of 
Amherst,  an  excellent  long  vertical  section,  part  of  which  is 
shown  in  Figure  15.  The  sequence  of  strata  is  clear  on  the  left 
side  of  the  section.  The  thicknesses  are  as  follows,  beginning 
at  the  top : 

2%.  feet  till. 

2%  feet  crumpled  clay,  about  150  varves. 

10  feet  excellent  clay,  varves  4450-4668. 

iK  feet  till. 

More  than  iK  feet  quicksand. 

To  the  right,  the  whole  clay  bed  is  crumbled  down  to  the  till. 
The  pressure  which  folded  the  clay  seems  to  have  come  from 
the  west-northwest.  The  connection  between  the  covering  till 
and  the  folding  of  the  clay  is  evident,  but  the  circumstances 
under  which  the  till  was  deposited  are  not  clear.    Those  small 


A  A  A  A  A  A  A  A  A  A  Z\^A  A  AAA 
Till        A  A  A^A^A  A^A  AAA  A  A  A  A.A^ 
AAAAAAAAAAAAAAAA 


Varve 
Clay' 


TMI      A   /^    A   A   Z\  A  A   A^A  AAA  A^A  A^A 
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Fig.  15 — Section  at  locality  24,  southeast  of  Amherst,  Mass.,  showing  till  on  top 
of  the  varve  clay  and  partial  folding  of  the  clay  by  pressure  from  the  west-northwest. 


78 


ICE  RECESSION  IN  NEW  ENGLAND 


RATE  OF  RECESSION  79 

icebergs  which  were  broken  off  in  the  glacial  lake  can  hardly  have 
been  able  to  push  together  a  clay  bed  so  thick.  That  a  landslide 
was  the  cause  is  equally  improbable,  since  the  ground  towards 
the  west  rises  only  60  feet  in  the  first  half-mile,  where  it  reaches 
the  foot  of  a  drumlin  whose  crest  is  only  140  feet  above  the  local- 
ity. The  last  possible  explanation,  that  the  ice  edge  readvanced, 
pushed  together  the  clay,  and  deposited  the  till  cover,  also  meets 
some  difficulty.  The  readvance  would  have  occurred  about  year 
4800,  i.e.  at  a  *time  when  deposition  of  clay  proceeded  undis- 
turbed at  Northampton,  7  miles  to  the  west.  Since  locality  28, 
the  ice  edge  at  which  lay  16.8  miles  (27.1  km.)  north  of  the  ice 
edge  when  at  locality  24,  was  uncovered  by  the  ice  before  year 
5084,  the  annual  recession  of  the  ice  from  24  to  28  must  have 
averaged  about  328  feet  (100  m.).  This  fact,  however,  forms 
no  obstacle.  Within  less  than  220  years  after  the  halt  at  Clare- 
mont,  N.  H.,  the  annual  recession  amounted  to  615  feet  (188 
m.;  see  p.  76),  and  in  Finland  Sauramo  (1918,  p.  31)  found  that 
the  rate  of  retreat  was  most  rapid  just  after  a  halt  or  a  slow 
recession. 

At  locality  20,  situated  at  the  northwestern  edge  of  Northamp- 
ton, the  following  section  was  measured,  beginning  at  the  top: 

3  feet  sand. 

2  feet  weathered  and  disturbed  varve  clay. 

i>^  feet  clay,  no  varves,  not  connected  with  the  normal  curve. 

13  feet  silty  clay,  homogeneous  through  disturbance. 

4  feet  quicksand,  slidden  at  the  top,  varves  4633  and  4634. 
Silty  clay,  sandy  at  the  top,  varves  4377—4632. 

Depth  to  bottom  unknown. 

Figure  16  shows  in  one-third  actual  thickness  varves  4560-4634 
at  this  locality  and,  for  the  sake  of  comparison,  varves  4560-4642 
at  locality  19,  situated  i>^  miles  to  the  south.  The  most  interest- 
ing thing  about  profile  20  is  the  increase  in  thickness  of  the 
varves  beginning  with  number  4586.  Varve  4587  and  those 
from  4592  upward  consist  of  quicksand.  Below  number  4586  the 
layers  have  about  the  same  thickness  as  at  the  other  localities 
in  tiie  region  but  consist  of  somewhat  coarser  material.    The 


80  ICE  RECESSION  IN  NEW  ENGLAND 

greater  thickness  of  the  varves  can  hardly  be  due  to  decreasing 
depth  because  of  sedimentation  at  the  locality,  since  this  lies 
about  125  feet  below  the  level  of  the  glacial  lake,  and  since  the 
varves  are  exceptionally  well  developed.  Shallow-water  varves 
have  heterogeneous  material  and  thin  and  indistinct  winter 
layers,  as  well  as  wavy  surfaces.  Nor  is  it  likely  that  the  reason 
is  drainage,  because  this  ought  to  have  been  felt  over  a  large 
part  of  the  lake,  if  not  over  the  whole  of  it.  The  fact  can  hardly 
have  been  caused  by  a  shorter  distance  from  the  locality  to  the 
mouth  of  the  eventual  Mill  River  of  that  time,  since  this  would 
have  discharged  into  a  bay  three  miles  northwest  of  it,  i.e.  as 
far  away  from  here  as  from  localities  19  and  21.  So  it  seems 
most  probable  that  the  zone  indicates  an  approach  of  the  ice 
border  which  during  year  4635  or  somewhat  later  overrode  the 
clay,  crumpling  up  its  upper  part.  It  would  have  been  a  local 
tongue,  extending  from  the  northwest,  since  deposition  of  clay 
proceeded  at  other  points  in  the  vicinity.  If,  however,  the  lake 
during  years  4586  to  4634  did  not  stand  at  its  highest  level 
(cf.  p.  52),  it  may  be  possible  that  the  thick  varves 
were  due  to  some  of  the  other  possible  reasons  mentioned  as 
alternatives. 

North  of  Northampton,  close  to  my  localities  21  and  22, 
Emerson  (1898,  p.  686,  and  PI.  18,  Fig.  3)  in  1880  found  in  a 
long  railway  cut,  in  the  midst  of  alternating  till  and  sand  beds, 
contorted  varve  clay.  The  overlying  till  was  no  doubt  deposited 
by  the  land  ice  during  a  marked  oscillation  of  its  border.  The 
unusually  complete  disturbances  of  the  clay  at  localities  21  and  22 
also  make  it  probable  that  they  once  or  several  times  were 
overlapped  by  the  ice. 

To  sum  up,  there  are  in  the  Northampton-Amherst  zone 
different  facts  which  seem  to  indicate  oscillations  of  the  ice  edge. 
If  the  conditions  are  correctly  explained,  the  ice  border  returned 
to  locality  20  during:  year  4635  or  somewhat  later,  after  having 
left  it  more  than  258  years  earlier;  it  returned  to  locality  24  about 
year  4800,  or  some  350  years  after  it  first  left;  and  to  localities 
21  and  22  at  some  other  date  not  known.    Furthermore,  the 


RATE  OF  RECESSION  8i 

rate  of  the  final  ice  retreat  between  localities  24  and  28  amounted 
to  328  feet  (100  m.)  a  year.  Further  investigations  are  needed 
to  reveal  the  actual  conditions. 


Rate  of  Recession  in  the  Middle  Zone 

In  northern  Massachusetts  the  amount  of  the  annual  recession 
was  193  feet  (59  m.).  The  rate  of  retreat  increased  until  the  ice 
edge  reached  the  Bellows  Falls  region,  whereupon  it  decreased 
again,  judging  from  the  halt  of  the  ice  edge  at  Claremont 
and  from  results  obtained  in  the  Merrimac  Valley.  When 
fastest,  the  recession  reached  approximately  370  feet  (113  m.) 
a  year. 

In  the  Merrimac  Valley  the  retreat  was  a  little  slower  than 
in  the  Connecticut,  probably  because  it  was  situated  closer  to 
the  sea,  where  the  sky  was  more  clouded.  The  highest  rate  was 
reached  a  little  north  of  Concord.  The  subsequent  retardation 
was  rather  noticeable. 

Oscillations  in  the  Lake  Winnepesaukee  Region 

In  the  Claremont-Lake  Winnepesaukee  zone  the  ice  edge 
again  halted  and  readvanced.  At  locality  41,  in  the  Connecticut 
Valley,  four  feet  of  coarse  gravel  with  several  boulders  a  foot 
in  diameter  overlie  discordantly  a  thick  deposit  of  varve  sand 
which  represents  more  than  50  years  (see  p.  22).  The  gravel  is, 
no  doubt,  outwash  deposited  during  a  readvance  of  the  ice  edge. 
Around  Lake  Winnepesaukee  till  in  doubtless  its  original  position 
frequently  overlies  varve  clay,  marking  oscillations  of  the  ice 
border  (Upham,  1878,  p.  131).  A  few  such  localities  were 
visited  by  Goldthwait  and  the  writer.  At  Clay  Point,  3  miles 
southwest  of  Wolfeboro,  at  the  southeastern  end  of  the  lake, 
the  varve  clay,  which  according  to  Upham  is  at  least  15  feet 
thick,  is  now  covered  by  talus.  The  original  position  of  the 
overlying  till  is  obvious.  At  Weirs,  on  the  western  side  of  the 
lake,  a  third  of  a  mile  north  of  the  railroad  station,  a  30  to  40-foot 


82  ICE  RECESSION  IN  NEW  ENGLAND 

section  at  the  bottom  of  a  hill  shows  the  following  layers, 
beginning  at  the  top : 

2  feet  till,  mostly  blocks. 

4-8  feet  silty  and  sandy  disturbed  clay.  Varves  >3  to  4  inches  (i  to 
10  cm.)  thick.   Varve  limits  difficult  to  distinguish. 

3-4  feet  stratified  sand. 

>^-3  feet  disturbed  varve  clay. 

Thick  varve  clay  with  several  disturbed  zones  and  here  and  there 
morainic  material.  The  clay  consists  of  sand  or  silt  and  of  thick, 
greasy  clay  layers,  but  the  varve  limits,  in  many  cases,  cannot  be 
determined.  At  the  bottom  of  the  section  the  varves  are  sandy  and 
6  to  8  inches  (15  to  20  cm.)  thick,  probably  indicating  inconsiderable 
depth  to  the  base  of  the  deposit. 

The  covering  till  may  have  been  deposited  by  the  land  ice, 
judging  from  Upham's  statement  that  on  the  top  of  the  hill, 
the  sides  of  which  show  till  at  the  surface,  a  well  27  feet  deep 
encountered  only  varve  clay.  The  consistency  of  the  clay  seems 
also  to  show  that  it  was  deposited  off  a  practically  stationary 
ice  edge.  The  sand  bed  may  mark  a  readvance  almost  to  the 
spot.  After  a  short  renewed  retreat  the  ice  overrode  the  clay 
and  deposited  the  till  cover. 

This  halt  is  not  registered  in  the  normal  curve,  because  I  did 
not  succeed  in  getting  varve  series  so  long  that  they  bridged  it 
and  could  be  connected  with  profiles  north  of  the  zone.  In  the 
Connecticut  Valley  the  Bellows  Falls  lake  was  filled  up  with 
sediments  probably  about  300  years  before  the  ice  uncovered 
localities  61  to  63  north  of  the  zone  of  retardation.  Not  even 
localities  41  and  43  can  be  connected  with  those  south  of  them. 
Nor  is  the  halt  recorded  in  the  Merrimac  Valley.  The  lake  at 
Concord  also  was  filled  up  with  sediments  too  early,  though 
certainly  75  years  later  than  the  Bellows  Falls  lake.  As  the  ice 
retired  and  began  to  uncover  the  outlet  of  the  Winnepesaukee 
basin,  the  drainage  area,  tributary  to  the  Merrimac,  became 
very  large,  and  the  volume  of  water  passing  through  very 
considerable.  The  increase  of  the  current  was  followed  by 
increase  of  the  critical  depth  of  clay  sedimentation  in  the  course 
of  the  current.  At  points  swept  by  the  current  sand  was  deposited 


RATE  OF  RECESSION  83 

even  in  deep  water,  and  so  the  varves  at  closely  situated  localities 
in  the  middle  of  the  lake  sometimes  differ  greatly  in  thickness. 
At  locality  52  deposition  of  sand  started  during  year  6232  at  a 
water  depth  of  about  75  feet,  and  at  locality  57  during  year 
6308  at  a  depth  of  about  100  feet.  After  the  critical  depth  of 
clay  sedimentation  had  been  reached  at  a  given  point  the  lake 
there  was  filled  up  with  sand  and  silt  in  a  few  decades  (cf.  pp. 
25-28).  My  attempts  to  bridge  the  gap  in  the  Hudson  and  Mo- 
hawk Valleys  were  also  without  result,  in  the  former  because 
the  clays  did  not  offer  any  exposures  and  in  the  latter  on  account 
of  the  general  absence  of  clays.  How  many  varves  are  lacking 
in  the  normal  curve  cannot,  of  course,  be  stated,  but  their 
number  in  view  of  the  facts  known  seems  to  amount  to  200  or 
300.  If  this  estimate  is  correct,  the  retardation  and  the  readvance 
should  represent  at  least  400  years. 

Rate  of  Recession  in  Northern  Zo?^ 

As  soon  as  the  recession  from  this  line  had  started  it  seems  to 
have  become  quite  rapid,  since  between  localities  61  and  64,  i.e. 
during  the  first  100  or  200  years,  it  averaged  615  feet  (188  m.) 
a  year.  Between  White  River  and  Hanover  it  reached  over  812 
feet  (246  m.).  After  a  slight  decrease  it  increased  again  and 
reached,  between  localities  75  and  79,  1,100  feet  (335  m.)  a  year, 
the  fastest  rate  observed  in  New  England.  Then  the  speed 
diminished  again,  amounting,  between  localities  79  and  86,  to 
about  830  feet  (253  m.)  a  year.  When  the  ice  edge  had  retired 
beyond  St.  Johnsbury  it  probably  halted  and  readvanced.  Since 
I  hope  to  be  able  soon  to  collect  more  material  regarding  the 
conditions  in  this  region,  at  this  time  it  may  merely  be  stated 
that,  the  ice  border  seems  to  have  readvanced  to  St.  Johnsbury 
in  the  Passumpsic  Valley  and  to  the  junction  with  the  Pas- 
sumpsic  in  the  Connecticut  Valley.  The  final  retreat  of  the  ice 
from  locality  85  occurred  about  280  years  after  it  uncovered 
locality  86,  a  mile  to  the  west.  The  halt  seems  to  correspond  to 
the  one  registered  by  moraines  at  Bethlehem  and  Littleton, 


84  ICE  RECESSION  IN  NEW  ENGLAND 

15  miles  (24  km.)  east  of  here,  which  have  been  mapped  by 
Gold th wait  (191 6).  As  for  the  length  of  time  represented  by  the 
halt,  280  years  may  be  a  minimum  figure. 

Rate  of  Retreat  and  Type  of  Clay 
Difference  in  thickness  between  varves  is  usually  due  to  varia- 
tion of  the  coarse  summer  layers,  the  winter  layers  being  almost 
equally  thick  from  year  to  year.  Accordingly,  thin  varves  con- 
tain a  greater  percentage  of  fine  material  than  do  thick  ones. 
The  thickness  of  the  varves,  the  amount  of  sedimentation,  is  a 
measure  of  the  amount  of  melting.  Since  slow  recession  and 
halt  of  the  ice  border,  as  observed  by  De  Geer  long  ago,  are 
usually  recorded  by  thinner  and  more  greasy  varves  than  is 
fast  recession,  it  is  evident  that  the  retardations  were  character- 
ized by  little  melting,  in  other  words,  by  low  temperature  (cf. 
p.  86) .  Thus  the  clay  gives  an  idea  of  the  rate  of  the  retreat  and 
of  the  climatic  conditions,  especially  in  regions  which,  like 
Fenno-Scandia,  are  built  up  of  hard,  coarse  Archean  rocks  (see 
also  Sauramo,  1918,  p.  37).  This  rule,  however,  can  be  applied 
only  with  the  greatest  caution  to  districts  occupied  by  both  hard 
and  soft  rocks.  A  soft,  fine-grained  slate  or  schist  evidently 
gave  rise  to  a  fatter  clay  than  did  a  hard,  coarse-grained  granite, 
regardless  of  the  amount  of  melting.  There  occur,  therefore, 
in  New  England  clays  deposited  during  rapid  recession  consisting 
exclusively  of  such  fine  material  that  the  varve  limits  cannot  be 
distinguished. 

Another  reason  why  the  thickness  and  texture  of  the  varves 
cannot  be  used  as  indicators  of  the  ice  retreat  in  New  England  is 
the  fact  that,  in  the  small  lakes  which  occupied  the  valleys, 
thick  and  thin  varves  often  only  mean  large  or  small  drainage 
area.  It  is  particularly  significant  that  during  an  annual  reces- 
sion of  more  than  1,000  feet  (300  m.)  comparatively  thin  and 
fat  clay  varves  were  deposited  in  the  Connecticut  Valley  at 
Woodsville,  while  at  locality  63,  50  miles  farther  from  the  ice 
front  but  below  important  tributaries,  the  same  varves  are 
silty  and  three  to  four  times  as  thick. 


RATE  OF  RECESSION  85 

When  the  details  of  the  ice  retreat  are  known,  it  will  be  possi- 
ble to  discriminate  between  peculiarities  dependent  upon  the 
character  of  the  mother  rock  and  those  due  to  the  rate  of  reces- 
sion or  to  the  climate. 

Conditions  Controlling  Recession 

The  factors  causing  and  influencing  the  disappearance  of  the 
ice  sheets  were  many  and  different:  temperature,  precipitation 
in  form  of  snow  and  in  form  of  warm  rains,  topographic  condi- 
tions, conditions  favoring  discharge  of  icebergs,  etc.  The  ice 
itself  moved  forward,  and  the  retreat  of  the  ice  edge  was  the 
excess  of  the  melting  over  the  advance.  The  combinations  of 
the  factors  were  complicated  and  changing,  and  so  in  many 
cases  they  cannot  yet  be  analyzed;  but  detailed  and  exact 
chronological  studies  promise  to  shed  light  upon  these  funda- 
mental questions. 

TEMPERATURE 

The  importance  of  the  summer  temperature  is  probably  best 
shown  by  De  Geer's  studies  in  Sweden  (1912,  1912a,  1914). 
The  most  significant  evidence  is  perhaps  the  great  difference  in 
the  rate  of  the  recession  of  the  ice  on  the  Swedish  west  coast 
and  that  in  the  Baltic  region.  In  western  Sweden  the  ice  edge 
stood  practically  still  for  one  or  two  thousand  years,  while  it 
receded  at  great  speed  in  the  eastern  part  of  the  country.  De 
Geer's  explanation  is  that  on  the  west  coast  the  air  was  very 
foggy  and  the  temperature  low  and  constant,  while  in  the  Baltic 
region  the  sky  was  clear  and  warm  and  sunny  days  were  frequent. 
The  intensely  dense  fog  along  the  Gulf  Stream  in  the  Arctic  is 
well  known.  On  Bear  Island,  halfway  between  Norway  and 
Spitsbergen,  the  writer  from  the  beginning  of  August  to  the 
middle  of  October  in  191 6  saw  the  sun  in  all  for  but  a  few 
hours.  The  summer  temperature  on  this  island  is,  on  the  average, 
a  few  degrees  above  the  freezing  point  and  exceedingly  even. 
In  other  Arctic  regions,  as  Spitsbergen,  the  insolation  on  bright 


86  ICE  RECESSION  IN  NEW  ENGLAND 

<iays  can  be  very  high,  causing  the  glaciers  to  melt  considerably 
and  the  rivers  to  swell  strongly  (see  also  Hann,  191 1). 

The  nourishment  of  the  ice  sheet,  which,  as  Hobbs  (191 1,  p. 
287;  1911a,  1915)  points  out,  largely  occurs  in  such  a  way  that 
the  snow,  fallen  during  a  relative  calm,  is  by  violent  anticyclonic 
surface  air  currents  swept  from  all  central  portions  of  the  ice 
sheet  and  deposited  near  and  about  the  margins  of  the  ice 
shield,  may  perhaps  have  become  greater  in  western  Sweden, 
but  that  does  not  explain  the  rapid  recession  in  the  Baltic  region. 
Nor  can  the  discharge  of  bergs  from  the  ice  front  explain  the 
different  rate  of  retreat.  In  the  present  Baltic  area,  as  well  as 
in  the  surrounding  lowlands,  which  were  submerged  below  the 
Baltic  of  that  time,  calving  doubtless  played  an  important  r61e, 
particularly  where  the  waters  were  deep  and  wide  and  the  lifting 
power  and  wave  action  was  great.  But  since  the  supply  of  ice 
in  these  regions  was  greater  than  in  the  supramarine  parts  of 
eastern  Sweden,  the  recession  was  almost  as  fast  in  these 
latter. 

The  important  part  played  by  sunshine  as  compared  with  that 
of  rain  is  evident,  for  the  Swedish  west  coast,  in  late  glacial  time, 
had  doubtless  much  more  rain  than  had  the  Baltic  district. 
Rains  in  Arctic  regions  are  also  usually  cold  and  sparse. 

Indication  of  the  great  importance  of  temperature  seems  also 
to  be  found  in  the  thicknesses  of  the  varves,  which  varied  greatly 
from  year  to  year.  If  the  recession  had  been  mainly  determined 
by  conditions  of  precipitation,  it  is  to  be  expected  that  the 
recession  and  the  clay  sedimentation  should  have  been  prac- 
tically the  same  from  year  to  year  and  should  have  undergone 
only  slow  variation. 

Variations  of  temperature  seem  also  usually  to  be  the  causes 
of  the  long  and  marked  fluctuations  in  the  rate  of  recession,  which 
themselves,  to  be  sure,  can  be  readily  explained  by  changes  in 
precipitation,  since  in  Sweden  and  Finland  the  thicknesses  of 
the  varves  are  found  as  a  rule  to  stand  in  good  relation  to  the 
rate  of  retreat  and  the  thin  varves  deposited  during  halts  indi- 
cate inconsiderable  melting  (cf.  p.  84). 


RATE  OF  RECESSION  87 

TOPOGRAPHY 

The  influence  of  topography  was  important.  The  direction  of 
striae  and  the  position  of  recessional  moraines  indicate  the  fact, 
and  detailed  mapping  of  the  ice  front  by  means  of  the  clays 
reveal  it  still  better,  as  researches  in  Sweden  have  shown.  The 
rate  of  flow  of  the  ice  was  rapid  in  valleys  and  basins,  while  it 
was  checked  on  highlands.  In  the  marginal  zone  the  distal  parts 
of  the  valleys  were  filled  with  protruding  ice  lobes,  though  dis- 
charging of  icebergs  counterbalanced  their  formation.  As  the 
ice  edge  withdrew,  the  lobes  gradually  disappeared,  and,  when 
the  ice  front  reached  the  northern,  proximal  end  of  the  valley, 
it  had  become  concave.  The  flow  of  the  ice,  though  now  slower, 
was  yet  more  rapid  than  in  the  higher  neighboring  parts,  but  it 
was  more  than  counterbalanced  by  calving. 


PRECIPITATION 

A  valuation  of  the  influence  of  precipitation,  or  nourishment 
of  the  ice,  is  particularly  difficult,  since  this  had  much  the  same 
effects  as  the  temperature  and  may  have  co-operated  with  it  in 
the  great  advances,  readvances,  and  recessions.  For  certain 
local  readvances  of  the  ice,  not  due  to  topographic  conditions, 
precipitation  may  have  played  the  leading  part,  since  this  is 
likely  to  show  greater  differences  between  near-by  regions,  topo- 
graphically similar,  than  does  the  temperature.  The  ice  lobes 
southwest  of  Lake  Superior  may  be  taken  as  examples. 

There  seems  to  be  one  known  case  of  a  halt  in  the  retreat  in 
Fenno-Scandia  chiefly  determined  by  increased  precipitation, 
namely  that  at  the  Inner  Salpausselka  in  southern  Finland. 
While  the  ice  edge  halted  for  183  years  at  this  morainic  line 
(Sauramo,  19 18,  pp.  35,  38,  43,  44),  which  in  some  districts,  is 
divided  into  a  series  of  moraines,  a  clay  consisting  almost  ex- 
clusively of  fine  material  was  deposited,  as  usual  during  halts. 
In  contradiction  to  the  rule,  however,  the  varves  marking  the 
halt  are  considerably  thicker  than  those  deposited  during  the 


88  ICE  RECESSION  IN  NEW  ENGLAND 

previous  retreat,  which  was  rather  slow.  Sauramo  does  not  give 
an  explanation  of  the  case.  It  seems  evident  that  the  lack  of 
coarse  material  indicates  absence  of  strong  currents  of  the  ice 
water.  In  other  words,  there  was  at  no  time  in  the  summer 
rapid  melting.  Warm  sunny  days  must  have  been  few  or  none, 
and  the  temperature  very  even.  On  the  other  hand,  the  melting 
must  have  lasted  for  several  months,  since  the  sedimentation  was 
great.  The  fact  that  the  ice  edge  on  the  whole  did  not  withdraw 
under  these  circumstances  seems  to  prove  that  the  nourishment 
of  the  ice  was  much  greater  than  usual.  This  is  an  interesting 
case  of  equilibrium  between  a  great  supply  of  ice  and  considera- 
ble melting  at  low  temperature.  The  clay  probably  does  not 
indicate  short  summers  and  long  winters,  as  supposed  by  Briick- 
ner  (1921,  p.  57,  cf.  our  p.  3). 


CHAPTER  VIII 

THE    CLIMATE    DURING   THE    RECESSION,   AND 
CLIMATIC  PERIODICITY 

The  Climate  During  the  Disappearance  of  the  Ice 

The  climate  during  the  disappearance  of  the  ice  in  New  Eng- 
land has  been  touched  upon  in  the  preceding  pages.  Since,  as 
explained  there,  the  summer  temperature  seems  to  have  been 
the  chief  factor  in  the  melting  of  the  ice,  the  rate  of  retreat 
gives  an  idea  of  the  temperature.  And  since  the  rate  of  recession 
varied  considerably  in  the  different  zones  (see  pp.  74-84),  the 
temperature  also  may  have  undergone  great  fluctuations.  The 
climate  was  not  arctic,  for  the  melting  of  the  ice,  in  many  zones, 
was  quite  rapid.  Since,  however,  a  vast  amount  of  heat  was 
used  in  the  melting  of  the  ice  and  heating  of  the  cold  ice  water, 
the  temperature  remained  comparatively  low  in  a  belt  off  the 
ice  front.  This  arctic  to  subarctic  zone  shifted  northward  as  the 
ice  front  withdrew.  It  doubtless  accommodated  an  arctic  and 
subarctic  fauna  and  flora,  about  which,  however,  very  little  is 
yet  known.  Although  relicts  of  these  northern  plants  and  ani- 
mals still  survive  on  the  highest  summits  in  New  England,  only 
a  few  occurrences  in  the  varve  clays  seem  to  have  been  reported. 
In  the  varve  clay  at  Northampton,  Mass.,  particularly  at  my 
locality  23,  Emerson  (1898,  p.  718)  found  remains  of  the  following 
plants:  Viola  palustris  L.,  Vaccinium  oxy coccus  L.,  Vaccinium 
uUginosum  L.,  Rhododendron  lapponicum  Wahl.,  Arctostaphylos 
alpina  Spr.,  Arctostaphylos  uva  ursi  Spr.,  Oxyria  digyna  Campd., 
Salix  cutleri  Tuck.,  and  Lycopodium  selago  L.  Of  these,  Salix 
cutleri  and  Vaccinium  oxycoccus  are  very  abundant.  The  plants 
indicate  an  arctic  to  subarctic  climate.  They  were  deposited 
when  the  ice  border  uncovered  northernmost  Massachusetts. 
They  must  have  grown  in  this  region  or  still  closer  to  the  ice  edge, 
since  any  transportation  must  have  been  southward.     I  am 


90  ICE  RECESSION  IN  NEW  ENGLAND 

informed  by  Mr.  R.  W.  Sayles  that  in  varve  clay  taken  by  him 
at  locality  78,  about  10  feet  above  the  till,  Dr.  E.  C.  Jeffrey 
found  microscopic  fragments  of  coniferous  wood. 

In  Sweden  the  rate  of  the  ice  retreat  from  the  south  coast  of 
Blekinge  (56°N.)  to  Ragunda  (63°N.)  in  Norrland  (450  miles,  or 
720  km.,  in  4,000  years)  averaged  about  600  feet  (180  m.)  a  year 
(De  Geer,  1912,  1915).  In  the  southern  part,  from  Blekinge  to 
the  Fenno-Scandian  moraines  (150  miles,  or  240  km.,  in  2,000 
years),  the  annual  recession  amounted  to  400  feet  (120  m.),  and 
in  the  northern  part,  from  the  moraines  up  to  Ragunda  (280 
miles,  or  450  km.,  in  1,500  years)  to  1,000  feet  (300  m.).  The 
morainic  belt  represents  two  halts  and  slow  intervening  recession 
for  together  nearly  700  years  (Sauramo,  1918,  p.  23). 

In  New  England,  between  Hartford,  Conn.,  and  St.  Johnsbury, 
Vt.  (185  miles,  or  298  km.,  in  4,100  years),  a  zone  lying  closer  to 
the  periphery  of  the  last  ice  sheet  than  does  Sweden,  the  annua) 
recession  averaged  about  240  feet  (75  m.),  i.  e.  less  than  one-half 
of  that  in  Sweden.  Assuming  that  during  the  ice  retreat  the 
supply  of  ice  was  the  same  in  Sweden  and  New  England  and  that 
the  rate  of  recession  reflects  the  temperature  to  the  same  extent 
in  both  regions,  it  must  have  been  considerably  warmer  in 
Sweden  when  the  ice  disappeared  there.  Accordingly,  the 
knowledge  of  the  late  glacial  climate  in  Sweden  cannot  be  directly 
applied  to  New  England.  As  far  as  this  is  based  on  the  immigra- 
tion of  the  flora,  it  should  be  noted  that  this  migration  occurred  on 
a  narrow  front  across  the  Danish  islands,  which  from  time  to  time 
connected  Sweden  with  the  continent  (Antevs,  1922),  while  the 
migration  northward  in  New  England  occurred  on  abroad  front. 

In  southern  Sweden  the  land  uncovered  from  the  vanishing 
ice  was  first  taken  possession  of  by  an  arctic  to  subartic  flora  with 
Dry  as  octopetala  as  its  most  typical  constituent.  Even  before 
the  disappearance  of  this  flora,  birch  {Betula  odorata  and  Betula 
verrucosa)  and  pine  {Pinus  silvestris)  were  more  or  less  abun- 
dant (von  Post,  19 16).  The  temperature  may  have  corresponded 
to  that  now  prevailing  in  northern  Scandinavia  (Andersson  and 
Birger,    1912,   p.    130),    Alder   {Alnus  glutinosa),  elm   {Ulmus 


CLIMATE  DURING  RECESSION  91 

montana),  linden  (Tilia  europaea),  and  hazel  {Corylus  avellana) 
immigrated  almost  immediately  after  the  extinction  of  the 
arctic  flora  and  occurred  in  the  whole  of  southern  Sweden  in 
early  post-glacial  time,  that  is  to  say  about  2,000  years  after  the 
release  of  the  ice  (von  Post,  191 6).  At  the  present  time  alder 
and  elm  occur  to  beyond  the  65th  parallel  of  latitude,  and  linden 
and  hazel  in  the  coast  region  up  to  the  63rd  parallel,  or  central 
Norrland.  In  northern  Sweden  the  land  was  from  the  beginning 
occupied  by  a  temperate  pine  flora,  essentially  similar  to  the  pre- 
sent vegetation  of  the  region  (von  Post,  I9ii,p.  20).  Thus  the 
amelioration  of  the  climate,  in  late  glacial  time,  became  more 
and  more  noticeable.  Towards  the  end  of  the  epoch  the  arctic 
belt,  which  had  previously  followed  the  retiring  ice  edge,  had 
ceased  to  exist. 

The  Varve  Studies  As  a  Key  to  Climatic  Periodicity 

The  clay  studies,  when  they  shall  have  been  carried  out  in 
detail,  will  increase  our  knowledge  of  climatic  periodicity.  They 
furnish  perhaps  the  best  material  known  for  the  study  of  long 
periods  and  one  of  the  best  for  that  of  short  ones.  Since  the 
disappearance  of  the  ice  was  due  to  climatic  reasons,  the  perio- 
dicity in  climate  is  recorded  by  the  annual  amount  of  ice  melting, 
the  rate  of  recession  of  the  ice  edge — recession,  halt,  and  re- 
advance — and  the  amount  of  sedimentation  (cf.  pp.  85-88). 
The  short  periods,  that  is  to  say  those  up  to  a  few  decades  in 
length,  are  best  illustrated  by  the  amount  of  sedimentation,  by 
the  varve  graphs.  The  long  cycles  are  shown  by  the  rate  of 
recession. 

Study  of  the  climatic  periods  is  one  of  my  chief  purposes  in 
measuring  so  great  a  number  of  sections  and  working  out  the 
normal  curve.  For  the  elimination  of  local,  non-climatic  features, 
material  from  different  lakes  is  necessary.  Therefore  at  present 
only  parts  of  the  normal  curve  are  fit  for  the  analysis  of  periods ; 
other  parts  may  be  perfectly  good  but  should  be  controlled. 
For  the  analysis  of  long  periods,  more  detailed  studies  of  the 
rate  of  ice  retreat  are  necessary.  While  time  has  not  permitted 


92  ICE  RECESSION  IN  NEW  ENGLAND 

an  analysis  of  the  graphs  for  the  recognition  of  short 
periods,  and  the  study  of  long  cycles  cannot  be 
made  without  more  data,  some  problems  and  con- 
ditions may  be  pointed  out  in  order  to  encourage 
the  collecting  of  more  material. 

Recognizable  Cycles 

The  period  of  ii  years,  or  the  sun-spot  cycle, 
together  with  its  multiples,  seems  to  play  a  promi- 
nent r61e  in  the  clay  sedimentation.  In  the  growth 
of  trees  the  same  cycles  are  predominant,  as 
Douglass  (1919,  p.  99)  has  shown.  He  has  determined 
periods  of  11  ^  2  (5  to  6),  11,  2  X  11  (21  to  24), 
3  X  II  (32  to  35),  and  3  X  3  X  n  (100  to  I05) 
years,  as  well  as  of  2  years. 

The  lines  of  recession  as  drawn  on  Plate  VI  do 
not  pretend  to  give  an  accurate  picture  of  the  vary- 
ing rate  of  ice  retreat;  for  that  a  much  more 
detailed  study  is  necessary.  It  is  likely  that  the 
rate  varied  a  good  deal  more  than  the  map  suggests. 
In  the  Berkshires,  Taylor  (1903)  has  mapped  a 
series  of  recessional  moraines,  the  most  conspicuous 
of  which  are  reproduced  on  Plate  VI.  As  Taylor 
points  out,  they  must  represent  short  periodical 
halts  in  the  ice  retreat.  Because  of  their  wide  spac- 
ing they  cannot  be  winter  moraines,  i.e.  moraines 
pushed  together  by  a  slight  readvance  of  the  ice 
edge  during  the  winter  after  a  summer  of  consider- 
able recession,  but  record  periods  of  some  length. 
On  the  map  an  attempt  has  been  made  to  connect 
two  moraines  with  two  positions  of  the  ice  edge. 
Unfortunately,  these  latter  are  not  accurately 
fixed.  Assuming  that  the  connections  are  correct, 
Taylor's  morainic  line  No.  2  should  correspond  to 
the  ice  edge  position  4800,  and  his  line  No.  11 
to  that  of  5300.     Accordingly,  there  should  be  nine 


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CLIMATE  DURING  RECESSION  93 

periods  marked  by  moraines  in  500  years,  which  gives  the  cycles 
an  average  length  of  55  years.  This  is  exactly  five  sun-spot 
cycles.  At  the  present  time  no  period  of  55  years  seems  to  be 
known.  If  we  assume  that  the  nine  periods  represent  600 
years  instead  of  500,  the  length  of  the  cycles  would  be  67 
years,  that  is  to  say  two  of  Bruckner's  35-year  periods. 
Determination  of  the  length  of  the  period — i.e.  the  time  of 
recession  and  halt — by  clay  measurements  would  be  of  very 
great  value.  In  the  clay  graphs  there  are  no  particularly 
thin  varves  which  could  be  supposed  to  record  these  halts. 
It  would  perhaps  be  hasty  to  conclude  from  this  that  the 
pauses  were  due  to  increased  ice  supply  rather  than  to  lower 
temperature  and  decreased  melting. 

In  Sauramo's  (1918,  PI.  3)  diagram  of  the  ice  retreat  in 
southern  Finland,  based  on  a  very  detailed  study,  the  fluctuations 
of  the  rate  are  striking  (Fig.  17).  Leaving  out  of  consideration 
the  part  —650  to  ±0,  which  represents  the  Fenno-Scandian 
moraines,  the  Outer  and  the  Inner  Salpausselka  (cf.  p.  87),  the 
ice  edge  halted  or  receded  slowly  on  four  occasions,  at  —1225, 

—  1050,  —880,  and  —725.  According  to  Sauramo's  (1918,  PI.  4) 
graphs,   the   varves   are   practically   normal   during  the   years 

—  1225  to  — 1221.  They  are  uniformly  thin  during  parts  of  the 
halt  —1085  to  —1035,  particularly  during  —1062  to  — 1051. 
The  varves  —900  to  —872,  i.e.  those  for  the  whole  halt,  are 
especially  at  Sauramo's  locality  19  thin  and  uniform.  The 
halt  —725  is  not  distinguishable  in  the  curves.  This  halt  is 
marked  by  a  chain  of  transverse  eskers  (see  Sauramo,  191 8, 
PI.  i).  The  average  length  of  the  periods  is  167  years,  or  five  times 
the  Bruckner  cycle.  The  facts  seem  to  indicate  that  the  halts 
were  primarily,  but  not  exclusively,  due  to  low  temperature. 

The  climate  during  the  ice  retreat  also  underwent  changes 
of  longer  amplitude.  The  length  of  the  period  recorded  by  the 
readvances  at  Amherst  and  Claremont  is  about  i  ,700,  and  that 
by  those  at  Claremont  and  Inwood  about  800  years.  One-third 
to  one-fourth  of  the  periods  were  occupied  by  readvances  of  the 
ice  edge. 


CHAPTER  IX 

THE   BEARING   OF   THESE    STUDIES   ON    PREVIOUS 
WORK  AND  ON  NEW  PROBLEMS 

Previous  Knowledge  of  the  Ice  Retreat 

The  map  compiled  by  Goldthwait  (PI.  VI)  illustrates  the 
retreat  of  the  last  ice  sheet  in  the  Northeastern  States.  It  shows 
the  general  direction  of  the  ice  flow  as  based  on  striae,  drumlins, 
and  boulder  trains  and  the  outermost  limit  marked  by  the 
terminal  moraines;  it  shows  interruptions  of  the  ice  retreat  as 
recorded  by  recessional  moraines  and  other  phenomena;  it 
indicates  the  late  glacial  marine  submergence  of  the  coast 
region  north  of  Boston  and  the  rate  of  recession  of  the  ice  front 
as  worked  out  by  the  clay  studies. 

The  ice  flow,  seen  on  the  map,  is,  so  far  as  can  be  judged,  that 
which  prevailed  during  the  time  of  the  ice  retreat.  The  center  of 
the  ice  lobe  covering  the  Northeastern  States  followed  the  great 
topographical  lines,  the  Champlain-Hudson  lowland  and  the 
Green  Mountains,  which  trend  north  and  south,  and  flowed 
directly  southward  across  Vermont.  In  southern  New  England, 
where  the  relief  is  less  marked  and  where  the  ice  flow  was  strong 
in  the  valleys  but  weak  in  the  lee  of  the  highlands,  subordinate 
lobes  were  developed  in  the  Hudson  and  Connecticut  Valleys. 
East  of  the  Connecticut  River  the  ice  movement  diverged  toward 
the  southeast.  West  of  the  lower  Connecticut  the  motion  was 
somewhat  westerly.  In  the  lower  and  central  Hudson  region 
the  ice  spread  strongly  toward  both  sides. 

During  the  ice  recession  the  Hudson  lobe  retired  more  slowly 
than  the  Connecticut  lobe  and  deployed.  It  invaded  western 
Connecticut  and  Massachusetts,  crossing  the  earlier  direction 
of  the  ice  flow.  The  ice  front  in  the  Berkshires,  as  revealed  by 
Taylor's    (1903)    studies    of   the   recessional    moraines,    had    a 


BEARING  OF  THESE  STUDIES  95 

northeast-southwest  direction.  In  the  Catskill  Mountains  and 
northwest  of  them  the  trend  of  the  ice  edge  was  northwest- 
southeast,  as  shown  by  T.  C.  Chamberlin's  and  Rich's  studies 
of  moraines  and  striae.  Hence  the  whole  mountain  group  was 
covered  by  a  large  lobe  the  eastern  edge  of  which  transgressed 
the  border  of  Connecticut  and  Massachusetts.  When  the  ice 
edge  had  left  the  Catskill  Mountains,  the  lobe  vanished  rap- 
idly, so  that  at  Cohoes  the  ice  front  had  an  almost  east-west 
direction. 

The  ice  crossed  the  Adirondack  Mountains  in  a  south- 
southwest  direction,  but  it  was  so  thin  and  the  movement  was 
so  slow  that  the  relative  lack  of  ice  south  of  them  caused  the 
lobes  on  either  side  to  join  and  cross  each  other  in  the  Mohawk 
Valley. 

In  western  New  York  the  ice  motion  was  largely  determined 
by  the  Ontario  basin  and  to  some  extent  by  the  topography  of 
the  Finger  Lakes  district. 

Confirmations  Through  the  Varve  Studies 

The  geochronological  studies  confirm  the  little  which  was 
known  about  the  rate  of  the  ice  retreat  (see  pp.  74-84).  Where 
Emerson  at  Northampton,  Mass.,  had  indications  of  a  halt  and 
readvance,  there  the  clays  furnish  independent  evidence  of  the 
same  thing.  In  the  same  zone  as  the  till-covered  varve  clays  on 
Lake  Winnepesaukee,  which  Upham  described,  evidences  for  a 
halt  are  also  found  on  the  Connecticut  at  Claremont.  Fifteen 
miles  west  of  the  recessional  moraines  which  Goldthwait  mapped 
at  Bethlehem,  on  the  northwestern  slope  of  the  White  Moun- 
tains, a  readvance  is  recorded  in  the  clays.  In  zones  where  no 
indications  of  halts  have  been  found  the  recession  proves  to  have 
been  more  or  less  rapid. 

It  is  the  same  thing  with  the  trend  of  the  ice  edge.  The  ice 
front,  fixed  by  connections  between  Cohoes,  N.  Y.,  and  Concord, 
N.  H.,  runs  at  right  angles  to  the  general  direction  of  the  ice 
flow.   Likewise  the  simultaneous  uncovering  of  the  site  of  Hud- 


96  ICE  RECESSION  IN  NEW  ENGLAND 

son,  N.  Y.,  and  the  northern  border  of  Massachusetts  where  this 
crosses  the  Connecticut  River  agrees  with  the  trend  of  Taylor's 
recessional  moraines  in  the  Berkshire  Hills  and  with  the  general 
direction  of  the  ice  movement  there. 

Their  Contribution  to  the  Problem  of  the  Glacial 

Correlation  of  the  Great  Lakes  Region 

AND  New  England 

One  of  the  great  problems  in  the  Quaternary  geology  of  North 
America  is  the  correlation  of  the  ice  retreat  in  New  England  with 
that  of  the  Great  Lakes  region.  Through  the  detailed  studies  of 
Leverett  and  Taylor  the  conditions  in  the  last-mentioned  area 
are  well  known.  Morainic  lines  marking  successive  ice  fronts 
are  mapped  and  correlated  from  the  Dakotas  eastward  to 
western  New  York.  But  the  correlatives  of  these  moraines  in 
eastern  New  York  and  New  England  are  unknown. 

A  comparison  of  the  ice  retreat  in  the  two  regions,  at  the  first 
glance,  suggests  more  differences  than  correspondences.  The 
disagreement,  however,  is  more  ostensible  than  real,  and  may 
essentially  be  due  to  the  different  topographic  conditions.  Most 
conspicuous  is  the  great  abundance  of  stadial  moraines  in  the 
Great  Lakes  region  and  the  practical  absence  of  them  in  New 
England.  The  basins  now  occupied  by  the  Great  Lakes  brought 
about  the  development  of  big  ice  lobes  which  easily  pushed  for- 
ward and,  favored  by  the  flatness  of  the  land,  built  continuous 
though  often  weak  moraines,  while  in  hilly  New  England  the  ice 
probably  readvanced  shorter  distances  and  could  not  pile  up 
any  coherent  ridges.  Some  of  the  faint  moraines  in  the  lake 
region  might  perhaps  rather  be  ridges  of  ground  moraine  than 
moraines  accumulated  along  the  ice  front.  Whether  all  the 
differences  between  the  two  regions  are  due  to  topographic 
conditions  or  not  is  difficult  to  tell.  It  seems  possible  that  there 
was  disagreement  also  in  other  respects,  most  likely  in  ice  supply. 
It  is  practically  sure,  however,  that  the  retreat  in  both  districts 
was  determined  primarily  by  an  amelioration  of  climate  and 
that  temperature  played  the  chief  role  also  for  the  readvances. 


BEARING  OF  THESE  STUDIES  97 

Therefore  it  is  highly  probable  that  readvances  in  the  one  region 
were  matched  by  readvances  in  the  other,  and  periods  of  recession 
in  the  one  by  those  in  the  other,  even  if  there  were  some  differ- 
ences in  details. 

The  first  halt  and  readvance  of  the  ice  in  New  England  north 
of  Hartford,  Conn.,  was  in  central  Massachusetts.  In  the 
Hudson  Valley  this  zone  comes  just  south  of  Kingston,  which 
was  uncovered  about  year  4900  (PI.  VI).  From  Kingston  the 
ice  edge,  as  just  mentioned,  formed  a  bow  towards  the  northwest, 
and  so  the  moraines  in  the  Catskills  and  northwest  of  them 
almost  surely  record  the  zone  of  readvance.  Between  Utica 
and  Syracuse,  as  seen  on  the  map,  there  was  a  wide  re-entrant 
in  the  ice  sheet,  while  in  the  lowland  of  the  Finger  Lakes  pro- 
truded a  big  lobe.  Accordingly  this  readvance  seems  to  be 
traceable  the  whole  distance  from  Massachusetts  to  the  western 
side  of  the  Finger  Lakes. 

In  the  Erie  and  adjacent  basins  glacial  Lake  Arkona  existed 
during  a  pause  after  a  recession  of  the  ice  front  (Taylor,  191 5, 
P-  375)-  The  ice  barrier  is  not  exactly  located;  but  it  stood  in 
about  the  same  position  as  for  Lake  Warren,  i.e.  at  the  Niagara 
Falls  moraine.  Lake  Arkona  was  followed  by  Lake  Whittlesey, 
which  was  caused  by  a  marked  readvance  of  the  ice  (Taylor, 
191 5,  pp.  376  and  384).  This  ice  front  is  marked  by  the  Port 
Huron  morainic  system,  which  parallels  the  northeastern  and 
northern  coast  of  the  southern  peninsula  of  Michigan  5  to  40 
miles  inland  (Taylor,  191 5,  PI.  32),  and  by  the  Alden  moraine 
south  of  Buffalo  (PI.  VI).  The  moraines  have  been  followed  from 
Wisconsin  entirely  across  the  Great  Lakes  region  to  the  Genesee 
River  in  western  New  York.  All  facts  indicate  a  general  and 
great  change  in  climate  which  surely  ought  to  have  its  correla- 
tive in  eastern  New  York  and  New  England.  The  Alden  moraine 
points  toward  the  moraines  south  of  the  Finger  Lakes,  which  in 
their  turn  ought  to  have  their  correlatives  in  the  Great  Lakes 
region.  Hence  it  is  exceedingly  likely  that  the  Port  Huron-Alden 
moraine,  the  Finger  Lakes  moraine,  and  the  overridden  clays  at 
Northampton,  Mass.,  correspond  to  each  other. 


98 


ICE  RECESSION  IN  NEW  ENGLAND 


56 


680 


56 


92 


Fig.  i8 — Curve  showing  drainage  during  years  5671-5676  recorded  at  locality  a 
Catskill,  N.  Y.  It  probably  marks  the  first  escape  eastward,  through  the  Mohawk, 
of  the  waters  of  the  Great  Lakes  which  occurred  during  the  Lake  Wayne  stage. 
Observe  the  great  thickness  of  the  varves  after  the  drainage.  Scale,  yi  actual  thick- 
ness. 


BEARING  OF  THESE  STUDIES  99 

About  900  years  after  the  readvance  at  Amherst,  or  during 
years  5671-5676,  there  occurred  a  great  drainage  into  glacial 
Lake  Albany.  Figure  18  and  curve  14  (PI.  Ill)  show  it  at  Catskill, 
65  miles  below  the  then  mouth  of  the  Mohawk  at  Schenectady. 
It  is  registered  at  other  localities  up  to  Albany,  but  the  zone  is 
disturbed.  It  is  the  only  drainage  of  importance  into  Lake 
Albany  for  more  than  600  years  during  the  ice  retreat  in  the 
central  and  upper  Hudson  region.  It  records  the  sudden  escape 
of  a  large  quantity  of  w^ater,  which  must  have  rushed  across  an 
abundance  of  easily  eroded  material.  At  the  time  of  the  drainage 
the  ice  edge  stood  somewhat  south  of  Cohoes;  and  west  of  the 
Hudson,  in  all  probability,  it  trended  slightly  north  of  west. 
The  ice  border  may  accordingly  have  left  the  highland  south 
of  the  Mohawk  River  and  the  varves  may  record  the  drainage 
of  a  lake  through  the  Mohawk  Valley  after  the  small  waters, 
dammed  in  this  valley,  had  escaped.  These  seem  to  have  been 
too  small  and  to  have  drained  out  through  channels  too  short  to 
allow  them  to  pick  up  much  material  (see  Fairchild,  1912). 
The  glacial  lake  in  the  Finger  Lakes  district  discharged  into  the 
Mohawk  waters  and  accordingly  indirectly  into  Lake  Albany 
(Fairchild,  1909,  PI.  37;  1912,  PI.  15).  So  it  seems  most  likely 
that  the  drainage  varves  mark  the  first  escape  of  the  vast  waters 
of  the  Great  Lakes  region  which  occurred  during  the  stage  known 
as  Lake  Wayne,  the  successor  of  Lake  Whittlesey  (Taylor,  19 13, 
p.  306;  191 5,  p.  386).  This  supposition  is  strongly  supported  by 
the  fact  that  the  varves  above  the  drainage  layer  are  much 
thicker  than  those  beneath,  the  first  twenty  being  two  and  a  half 
times  as  thick.  This  shows  that  the  new  tributary  to  Lake  Albany 
brought  more  material  than  was  supplied  by  the  glacial  rivers 
discharging  into  the  lake  and  by  all  other  tributaries  together. 

Subsequent  to  this  time  of  ice  retreat  the  ice  front  readvanced 
and  closed  the  outlet  at  Syracuse  (Taylor,  191 5,  pp.  392  and  398). 
The  resulting  stage  in  the  Great  Lakes  region,  Lake  Warren, 
reached  from  the  Finger  Lakes  district  to  the  Huron  basin  and 
discharged  westward.  The  eastern  barrier  of  the  lake  is  probably 
marked  by  the  Niagara  Falls  moraine.    This  marked  readvance 


100  ICE  RECESSION  IN  NEW  ENGLAND 

of  the  ice  very  likely  corresponded  to  the  readvance  at  Clareniont 
and  Lake  Winnepesaukee,  N.  H.,  which  occurred  about  years 
6200  to  6500. 

When  the  ice  edge  again  withdrew,  the  outlet*  of  the  Great 
Lakes  was  shifted  for  the  second  time  to  the  Mohawk  Valley, 
and  Lake  Lundy  came  into  existence  (Taylor,  19 13,  p.  309; 
1915,  p.  399  and  406  and  PI.  19;  Fairchild,  1909,  PI.  40).  The 
exact  position  of  the  ice  barrier  of  the  lake  is  not  known,  but  it 
was  between  the  Niagara  escarpment  and  the  present  shore  of 
Lake  Ontario.  The  beaches  of  the  lake  have  only  moderate 
strength  and  indicate  a  transition  stage.  As  the  ice  retired  and 
lower  outlets  were  uncovered,  the  waters  fell,  so  that  those  over 
Lake  Ontario  became  separated  from  those  in  the  Erie  basin. 
In  the  Ontario  basin  the  transition  stages  to  Lake  Iroquois  under- 
went a  number  of  changes  of  level  caused  by  slight  retreats  and 
readvances  of  the  ice  front  (Taylor,  1913,  p.  310;  1915,  p.  444). 
Finally  the  waters  fell,  owing  to  the  opening  of  a  lower  outlet  at 
Rome,  and  Lake  Iroquois  was  established.  This  lake  endured 
for  a  relatively  long  time.  When  the  ice  front  had  receded  to 
the  northern  side  of  the  Adirondacks,  Lake  Iroquois  emptied  into 
Lake  Champlain,  and  the  Rome  outlet  was  abandoned  (Peet, 
1904,  p.  660).  The  lake  level  sank  as  the  ice  withdrew,  and 
finally  the  sea,  entering  the  submerged  St.  Lawrence  Valley, 
changed  the  glacial  lake  into  a  marine  gulf. 

Before  the  marine  stage  could  come  into  existence  the  ice  had 
receded  beyond  the  St.  Lawrence  River.  The  transition  stages 
preceding  Lake  Iroquois  and  the  lake  itself,  therefore,  must 
correspond  to  the  ice  recession  in  northern  New  England  and 
southeastern  Canada.  The  pre-Iroquois  oscillations  of  the  ice 
border  may  correspond  to  the  repeated  readvances  of  the  ice, 
which,  as  a  reconnaissance  study  of  the  clays  seems  to  show, 
occurred  in  the  zone  between  St.  Johnsbury  and  the  Canadian 
frontier. 

Problems  To  Be  Studied 

This  memoir  only  treats  the  main  features  of  the  recession  of 
the  last  ice  sheet  in  New  England,  while  the  details  and  a  great 


BEARING  OF  THESE  STUDIES  loi 

many  questions  connected  with  these  researches  remain  to  be 
studied.    Some  of  these  problems  may  be  pointed  out. 

On  account  of  the  great  depth  of  the  varve  sediments  the  bot- 
tom layer  was  reached  practically  only  in  the  northern  part  of 
the  Connecticut  Valley.  It  is,  therefore,  to  be  hoped  that  any 
opportunity  to  measure  the  lowest  strata  be  used.  Series  with 
bottom  varves  are  necessary  for  the  determination  of  the  exact 
rate  of  recession.  If  a  sufficient  number  of  sections  with  bottom 
can  be  secured,  the  position  of  the  ice  front  for  every  winter  can 
be  mapped.  Such  a  study  has  been  carried  out  by  De  Geer 
(1912,  PI.  2;  1912a,  p.  464)  of  the  Stockholm  district.  Detailed 
determination  of  the  rate  of  recession  probably  yields  the  best 
material  known  for  studying  the  long  climatic  periods,  i.  e. 
periods  from  a  few  decades  to  hundreds  or  thousands  of  years. 

The  zones  of  readvance  of  the  ice  should  be  studied  in  detail. 
The  extent  and  number  of  oscillations,  time  involved,  and  the 
rate  of  retreat  before  and  after  the  readvances  are  questions  of 
great  importance  for  the  understanding  of  the  causes.  Stadial 
moraines  should  be  sought  and  mapped  particularly  in  these 
zones. 

Determination  of  the  length  of  time  of  the  periods  recorded  by 
the  stadial  moraines  which  Taylor  (1903)  mapped  in  the  Berk- 
shires  should  be  of  great  climatological  interest  (cf.  p.  92). 

Clay  measurements  in  other  lakes  and  valleys  are  very  valua- 
ble for  elimination  from  the  normal  curve  of  local,  non-climatic 
features. 

The  history  of  the  lakes  presents  interesting  problems.  A 
detailed  study  of  their  water  levels  is  being  made  by  Goldthwait. 
This  will  throw  light  upon  the  extension  of  the  lakes  (cf.  p.  9), 
the  sedimentation,  the  tilting  of  the  land,  the  changes  of  level 
of  the  lakes  due  to  lowering  or  raising  of  their  outlets  (cf.  pp. 
8,  51),  and  so  forth.  Determination  of  the  minimum  duration 
of  the  lakes  by  counting  the  varves  will  give  an  idea  of  the  rate 
of  the  warping  of  the  land. 

The  measured  profiles  represent  a  vast  amount  of  material  for 
the  study  of  sedimentation.    Part  of  this  is  given  in  the  descrip- 


102  ICE  RECESSION  IN  NEW  ENGLAND 


Fig.  19 — Part  of  curves  at  localities  27  and  28,  near  Greenfield,  Mass.,  situated 
only  600  yards  apart.  The  thick  varves,  at  locality  28,  consist  of  coarse  sand,  often 
in  lenses.  Some  varves  at  locality  27  are  also  sandy.  The  elevation  of  the  localities 
is  about  the  same.  The  current  may  have  swept  over  locality  28,  but  this  does  not 
seem  to  be  a  satisfactory  explanation.   Scale,  M  actual  thickness. 


BEARING  OF  THESE  STUDIES  103 

tion  of  the  sections  (Ch.  III).  A  closer  treatment  requires  better 
knowledge  of  the  surfaces  of  the  lakes  than  we  have  now.  Prob- 
lems are:  the  spreading  of  the  sediments  in  the  lakes,  i.  e.  the 
decreasing  in  thickness  of  the  varves  and  in  coarseness  of  the 
material  outward  from  the  mouth  of  the  glacial  river;  sedimen- 
tation and  depth  of  water  (cf.  Fig.  19  and  pp.  51,  69,  82);  sedi- 
mentation and  size  of  the  drainage  area;  fluctuations  in  the  sedi- 
mentation during  the  summer,  as  recorded  in  thick  silty  varves; 
the  mechanical  and  chemical  character  of  the  sediments — • 
studied  in  Sweden  by  Oden. 

Drainages  of  lakes  ponded  by  ice  or  by  glacial  deposits  consti- 
tute a  subject  of  interest  for  detailed  study  (cf.  p.  69).  So  also 
do  changes  in  the  size  of  the  drainage  areas  of  the  lakes,  as  the 
ice  receded,  and  their  relation  to  the  sedimentation. 

Driven  southward  by  the  ice,  plants  and  animals  re-immigrated 
to  the  newly  exposed  land.  Hardy  species  followed  closely  the 
receding  ice  edge,  and  others  came  as  fast  as  conditions  be- 
came favorable  for  them.  Remains  of  the  earliest  flora  are  pre- 
served in  the  varve  clays,  and  a  stratigraphical  study  of  them 
should  be  of  both  botanical  and  climatological  interest.  By  meas- 
uring the  varve  series  in  which  the  plant  remains  occur  and 
identifying  these  varves  with  the  normal  curve,  the  position  of 
the  ice  edge,  when  the  plants  were  embedded,  can  be  fixed. 
Sandegren's  (191 5)  study  of  the  post-glacial  flora  and  climate 
at  Ragunda  in  northern  Sweden,  as  recorded  by  the  plant  remains 
in  the  varve  silts,  is  a  standard  work  because  of  its  accuracy.  Of 
considerable  interest  are  quantitative  and  stratigraphic  studies 
of  plant  pollen  in  the  clays,  like  those  carried  out  in  Sweden 
by  L.  von  Post  and  others. 

The  physiographic  development  and  the  geologic  factors,  such 
as  erosion  by  rivers  and  by  the  sea,  weathering,  etc.,  can  be 
studied  under  new  conditions  when  the  actual  length  of  time 
since  the  release  from  the  ice  shall  have  become  known.  Knowing 
that  southern  New  England  was  uncovered  about  5,000  years 
earlier  than  the  northern  part,  comparative  studies  can  be  made. 

The  question  of  local  glaciers  in  the  Adirondacks,  Catskills, 
and  White  Mountains,  after  the  departure  of  the  ice  sheet, 
might  be  settled  by  studies  of  the  clays. 


EXPLANATION  OF  THE  MAP  ILLUSTRATING  THE 

RECESSION  OF  THE  LAST  ICE  SHEET 

FROM  NEW  ENGLAND  AND 

NEW  YORK 

By  J.  W.  GOLDTHWAIT 

On  this  map  (PI.  VI)  have  been  assembled  those  observations 
of  glaciation  and  of  glacial  recession  which,  so  far  as  known  to 
the  compiler,  appear  trustworthy  and  useful  as  a  background 
for  plotting  Dr.  Antevs'  data.  It  is  fully  realized  that  no  com- 
plete and  accurate  map  of  the  glaciation  of  this  region  can  be 
made  without  much  further  field  work.  New  York  State,  in  the 
western  Adirondacks  and  west  and  southwest  of  the  Catskills 
especially,  awaits  fuller  study.  Unpublished  work  by  Woodworth 
and  by  Alden  in  Massachusetts  and  by  Rich  in  the  Catskill 
region  will  doubtless  make  some  correlations  much  clearer  and 
more  certain  than  those  possible  to  show  at  this  time. 

The  chief  sources  of  information  used  are  as  follows.  The 
titles  of  the  publications  referred  to  will  be  found,  under  the 
author's  name  and  the  year,  in  the  List  of  References  (pp. 
108-114). 

Direction  of  ice  flow,  as  shown  by  striae  and  boulder  dispersion 

In  New  Hampshire:  C.  H.  Hitchcock  (1878),  J.  W.  Goldthwait  and 
F.  H.  Foster  (unpublished  data  on  boulder  dispersion). 

In  Vermont:  C.  H.  Hitchcock  (1861)  and  scattered  observations  in 
more  recent  reports  of  the  State  Geologist  by  various  investigators. 

In  Massachusetts:  E.  Hitchcock  (1841),  B.  K.  Emerson  (1898),  and 
drumlin  axes  shown  on  topographic  quadrangles  of  the  U.  S.  Geological 
Survey. 

In  Rhode  Island:  N.  S.  Shaler  (1889);  also  drumlin  axes. 

In  Connecticut:  W.  W.  Mather  (1843),  B.  K.  Emerson  (1898),  H.  E. 
Gregory  (1906),  F.  Ward  (1920). 

In  New  York:  T.  C.  Chamberlin  (1883),  W.  W.  Mather  (1843).  J.  F. 
Kemp  and  R.  Ruedemann  (1910),  I.  H.  Ogilvie  (1902),  H.  P.  Gushing 


EXPLANATION  OF  MAP  105 

1907,  1916),  A.  P.  Brigham  (1895),  R.  S.  Tarr  (1909).  J-  M.  Clarke 
(1911),  W.  J.  Miller  (1909,  1910,  1914,  1916),  H.  L.  Fairchild  (1907). 
J.  B.  Woodworth  (1901,  1905),  J.  L.  Rich  (1906,  1914,  1915).  C.  E.  Gor- 
don (1911),  J.  H.  Stoller  (1911,  1916),  H.  J.  Ailing  (1916),  R.  D.  Salisbury 
and  others  (1902). 

In  New  Jersey:  R.  D.  Salisbury  and  others  (1902,  PI.  8;  and  1908), 
J.  V.  Lewis  and  H.  B.  Kiimmel  (1915). 

In  Pennsylvania:  H.  C.  Lewis  (1884). 

Because  of  lack  of  detailed  information  it  generally  has  not 
been  possible  to  discriminate  between  striae  made  at  different 
stages  of  ice  recession;  hence,  in  compiling  lines  of  flow,  a  con- 
servative attitude  has  been  kept  toward  the  delineation  of 
minor  lobes.  In  the  Connecticut,  Hudson,  and  Catskill  regions 
these  seem  to  have  been  more  strongly  accentuated  than  the 
map  indicates,  resembling  perhaps  the  more  thoroughly  studied 
lobe  of  the  Finger  Lakes  region.  The  very  wide  spread  of  the 
Mt.  Ascutney  boulder  train  is  the  best  evidence  of  this.  The 
flow  of  the  ice  appears  to  have  been  due  southward,  however, 
over  the  entire  eastern  uplands  of  Vermont,  so  that  it  is  a  mis- 
take to  regard  the  southward  movement  of  ice  down  the  Con- 
necticut Valley  as  due  in  any  sense  to  the  presence  of  that 
valley. 

Terminal  moraines 

In  Massachusetts:  J.  B.  Woodworth  (1897). 

In  New  York:  J.  B.  Woodworth  (1901),  M.  L.  Fuller  (1905.  I9i4)- 
In  New  Jersey  and  Pennsylvania:  same  references  as  under  former 
heading. 

Recessional  moraines 

In  Maine:  F.  J.  Katz  and  A.  Keith  (1917). 

In  New  Hampshire:  J.  W.  Goldthwait  (1916,  and  unpublished  data). 

In  Massachusetts  and  Rhode  Island:  J.  B.  Woodworth  (1896,  1897), 
F.  B.  Taylor  (1903).  W.  O.  Crosby  (1899). 

In  New  York:  T.  C.  Chamberlin  (1883),  F.  Leverett  (1915).  R-  S. 
Tarr  (1909),  H.  L.  Fairchild  (1907),  A.  P.  Brigham  (1898),  J.  L.  Rich 
(1906,  1914,  1915),  F.  B.  Taylor  (1913),  C.  E.  Peet  (1904),  F.  Carney 
(1909). 


io6  ICE  RECESSION  IN  NEW  ENGLAND 

Only  a  few  of  the  more  distinct  lines  of  recession  among  those 
described  in  southern  New  England  are  shown.  The  "New- 
ington  moraine"  of  Katz  and  Keith  is  shown  only  in  Maine  be- 
cause that  part  of  it  which  lies  in  New  Hampshire  and  Massa- 
chusetts seems  to  the  compiler  to  consist  of  a  series  of  local 
recessional  wash  plains  and  morainal  embankments  whose  ice 
contacts  lie  in  parallel  lines  which  trend  perpendicular  to  the 
striae.  (The  local  moraines  shown  on  PI.  VI  in  New  Hampshire 
in  the  same  axis  are  not  a  part  of  the  "Newington  moraine".) 
The  lines  of  moraine  in  western  New  York  are  mapped  in  some- 
what contradictory  fashion  by  different  investigators,  making 
it  difficult  to  select  material  consistently;  but  in  the  main  these 
follow  the  courses  determined  by  Leverett  and  Taylor. 

Isobases 

These  are  drawn  only  for  southeastern  New  Hampshire  and 
the  adjacent  part  of  Massachusetts,  and  are  based  upon  detailed 
observations  and  measurements  by  the  compiler.  Tarr's  50-foot 
beaches  on  Cape  Ann  are  taken  as  the  marine  limit  at  that  point. 
The  absence  of  confirmatory  evidence  from  the  Salem-Boston 
district  is  puzzling;  and  the  correct  course  of  the  isobases  in 
Massachusetts  is  not  known.  Studies  of  the  deformed  water 
planes  in  the  Merrimac,  Connecticut,  and  Contoocook  Valleys 
are  in  progress,  but  do  not  yet  justify  extension  of  the  isobases 
farther  inland  than  here  shown.  The  probability  that  the 
"marine  limits"  at  different  localities  are  not  even  approxi- 
mately contemporaneous  makes  a  fuller  construction  of  isobases 
unwise. 

Positions  of  receding  ice  edge 

These  lines,  plotted  by  Dr.  Antevs  after  data  collected  by 
him  at  the  localities  shown,  give,  so  far  as  the  facts  warrant,  the 
distances  uncovered  by  the  receding  ice  edge  each  century  in  the 
valleys  where  observations  are  numerous.  Three  positions  only 
are  plotted  in  the  Hudson  Valley,  to  show  how  the  recession 


EXPLANATION  OF  MAP  107 

there  corresponds  with  that  in  New  England.  Dotted  lines  indi- 
cate the  probable  correlation  of  Antevs'  ice  border  lines  with 
Taylor's  recessional  moraines  in  the  Berkshires  and  Rich's 
moraines  in  the  Catskills,  Peet's  Glens  Falls  moraine  south  of 
Lake  George,  and  the  Great  Lakes  moraines  as  mapped  by  Taylor 
and  Leverett. 


LIST  OF  REFERENCES 

Alling,  H.  L.  (1916).    Glacial  lakes  and  other  glacial  features  of  the 

central  Adirondacks.     Bull.   Geol.   Soc.   of  America,  Vol.   27,    1916, 

pp.  645-672. 
Andersson,   Gunnar,  and   Birger,    Selim   (1912).    Den  norrlandska 

florans  geografiska  fordelning  och  invandringshistoria.    Norrlandskt 

Handbibliotek  No.  5,  1912.    Upsala. 
Antevs,  Ernst  (1915).    Landisens  recession  i  nordostra  Skane.    Geol. 

Foren.  Forhandl.,  Vol.  37,  1915,  pp.  353-366.    Stockholm. 
Antevs,  Ernst  (1922).    On  the  late-glacial  and  post-glacial  history  of 

the  Baltic.   Geogr.  Review,  Vol.  12,  No.  4,  Oct.  1922. 
Barrell,  Joseph  (191 5).   Factors  in  movements  of  the  strand  line  and 

their  results  in  the  Pleistocene  and  post-Pleistocene.   Amer.  Journ.  of 

Set.,  Ser.  4,  Vol.  40,  191 5,  pp.  1-22. 
Birger,  Selim  (1912).  See  Andersson,  Gunnar  (1912). 
Brigham,   a.   p.    (1895).     Drift  bowlders   between  the   Mohawk  and 

Susquehanna  Rivers.  Amer.  Journ.  of  Sci.,  Ser.  3,  Vol.  49,  1895,  pp. 

218-228. 
Brigham,  A.  P.  (1898).    Topography  and  glacial  deposits  of  Mohawk 

Valley.   Bull.  Geol.  Soc.  of  Amer  tea.  Vol.  9,  1898,  pp.  183-210. 
Bruckner,    Eduard    (1890).     Klimaschwankungen    seit    1700    nebst 

Bemerkungen  iiber  die  Klimaschwankungen  der  Diluvialzeit.    Geogr. 

Abhandl.  herausg.  von  A.  Penck,  Vol.  4,  1890,  No.  2.   Vienna. 
Bruckner,  Eduard  (192 i).    Geochronologische  Untersuchungen  iiber 

die  Dauer  der  Postglazialzeit  in  Schweden,  in  Finnland  und  in  Nord- 

amerika.    Zeitschr.  fiir  Gletscherkunde,  Vol.  12,  1921,  pp.  39-57. 
Carlzon-Caldenius,     Carl     (1913).      Inlandisens    recession    mellan 

Bispgarden  och   Stugun   i   Indalsalvens  dalgang  i  Jamtland.     Geol. 

Foren.  Forhandl.,  Vol.  35,  1913,  pp.  311-328  and  348-360.   Stockholm. 
Carney,  Frank  (1909).  The  Pleistocene  geology  of  the  Moravia  quad- 
rangle. New  York.  Bull.  Scientific  Laboratory  of  Denison  Univ.,  Vol.  14, 

1909,  pp.  335-442. 
Chamberlin,  T.  C.  (1883).    Terminal  moraine  of  the  Second  Glacial 

Epoch.   3rd  Ann.  Rept.  U.  S.  Geol.  Survey,  for  1881-82,  pp.  291-402. 

Washington,  D.  C.  1883. 
Clarke,  J.  M.  (1911).    Seventh  Report  of  the  Director  of  the  Science 

Division,  New  York  State  Museum  Bull.  No.  149,  1911. 
Crosby,  W.  O.  (1899).    Geological  history  of  the  Nashua  valley  during 

the  Tertiary  and  Quaternary  periods.    Technology  Quarterly,  Vol.  13, 

1890,  p.  322.     Massachusetts  Institute  of  Technology.  Boston. 


LIST  OF  REFERENCES  109 

Gushing,  H.  P.  (1907).     Geology  of  the  Long  Lake  quadrangle.    New 

York  State  Museum  Bull.  No.  115,  iQO?- 
Gushing,  H.  P.  (1916).    Geology  of  the  vicinity  of  Ogdensburg.    New 

York  State  Museum  Bull.  No.  191,  1916. 
Gushing,  H.  P.;  Fairchild,  H.  L.;  Ruedemann,  Rudolf;  and  Smyth, 

G.  H.,  Jr.  (1910).   Geology  of  the  Thousand  Islands  region.   New  York 

State  Museum  Bull.  No.  145,  1910. 
Dana,  J.  D.  (1870).    On  the  geology  of  the  New  Haven  region,  with 

special  reference  to  the  origin  of  some  of  its  topographical  features. 

Trans.  Connecticut  Acad,  of  Arts  and  Sci.,  Vol.  2,  Part  I,  1870,  pp. 

45-112.    New  Haven. 
De  Geer,   Gerard  (1882).    Cm  en  postglacial  sankning  i  sodra  och 

mallersta  Sverige.    Geol.  Foren.  Forhandl.,  Vol.  6,  1882,  pp.  149-162; 

reference  on  p.  159.    Stockholm. 
De  Geer,  Gerard  (1884).    Cm  mojligheten  af  att  infora  en  kronologi 

for  istiden.    Geol.  Foren.  Forhandl.,  Vol.  7.  1884,  p.  3.    Stockholm. 
De    Geer,    Gerard    (1885).     Om    istidens    kronologi.     Geol.    Foren. 

Forhandl.,  Vol.  7,  1885,  pp.  512-513.    Stockholm. 
De  Geer,  Gerard  (1912).    A  geochronology  of  the  last  12,000  years. 

Compte  Rendu  Congres  Geol.  Internatl.  a  Stockholm,  1910,  pp.  241-253. 

Stockholm,  1912. 
De  Geer,  Gerard  (1912a).    Geochronologie  der  letzten  12,000  Jahre. 

Geol.  Rundschau,  Vol.  3,  1912,  pp.  457-471.    Leipzig. 
De  Geer,  Gerard  (19 14).   Om  naturhistoriska  kartor  over  den  baltiska 

dalen.   Pop.-Naturvet.  Revy,  1914,  pp.  189-200.    Stockholm. 
De  Geer,  Gerard  (1921).    Gorrelation  of  late  glacial  clay  varves  in 

North  America  with  the  Swedish  time  scale.    Geol.  Foren.  Forhandl., 

Vol.  43,  1921,  pp.  70-73.    Stockholm. 
De  Geer,  Gerard  (1921a).   Nordamerikas  kvartargeologi  belyst  av  den 

svenska  tidskalan,  Geol.  Foren.  Forhandl.,  Vol.  43,  1921,  pp.  497-499. 

Stockholm. 
Diller,  J.  S.  (1898).  The  geology  of  Westfield  and  vicinity,  in  Emerson, 

B.  K.    (1898),  pp.  654-656. 
Douglass,  A.  E.   (1919).    Climatic  cycles  and  tree-growth,    Carnegie 

Instn.  Publ.  No.  289,  Washington,  D.  C.,  1919- 
Emerson,   B.   K.   (1887).     The  Connecticut  Lake  of  the   Champlain 

period,  north  of  Holyoke.   Amer.  Journ.  of  Sci.,  Ser.  3,  Vol.  34,  1887, 

p.  404. 
Emerson,   B.  K.   (1898).    Geology  of  Old  Hampshire  County,  Mass., 

comprising  Franklin,  Hampshire,  and  Hampden  Counties,  U.  S.  Geol. 

Survey  Monograph  29,  1898. 
Emerson,  B.  K.  (1898a).    Holyoke  Folio.      U.  S.  Geol.  Survey  Geologic 

Atlas,  Folio  No.  50,  1898. 


no  ICE  RECESSION  IN  NEW  ENGLAND 

Fairchild,    H.   L.    (1907).     Drumlins   of   central   western   New   York. 

New  York  State  Museum  Bull.  No.  iii,  1907. 
Fairchild,  H.  L.  (1909).    Glacial  waters  in  central  New  York.    New 

York  State  Museum  Bull.  No.  127,  1909. 
Fairchild,  H.  L.  (1910).  See  Gushing,  H.  P.,  and  others  (1910). 
Fairchild,  H.  L.  (1912).    The  glacial  waters  in  the  Black  and  Mohawk 

valleys.   New  York  State  Museum  Bull.  No.  160,  1912. 
Fairchild,  H.  L.  (1914).   Pleistocene  marine  submergence  of  the  Gonnec- 

ticut  and  Hudson  valleys.  Bull.  Geol.  Soc.  of  America,  Vol.  25,  1914, 

pp.  63  and  219-242. 
Fairchild,  H.  L.  (1919).    Post-glacial  uplift  of  southern  New  England. 

Bull.  Geol.  Soc.  of  America,  Vol.  30,  1919,  pp.  597-636. 
Fuller,  M.  L.   (1905).    Geology  of  Fishers  Island,  New  York.    Bull. 

Geol.  Soc.  Amer.,  Vol.  16,  1905-06,  pp.  367-390. 
Fuller,  M.  L.  (1914).    The  geology  of  Long  Island,  New  York.    U.  S. 

Geol.  Survey  Professional  Paper  82,  1914. 
Goldthwait,   J.  W.    (1916).     Glaciation  in  the  White   Mountains  of 

New  Hampshire.    Bull.  Geol.  Soc.  of  America,  Vol.  27,  1916,  pp.  263- 

294. 
Gordon,  C.  E.  (191  i).    Geology  of  the  Poughkeepsie  quadrangle.    New 

York  State  Museum  Bull.  No.  148,  1911. 
Gregory,  H.  E.  (1906).    Glacial  geology,  in  Manual  of  the  geology  of 

Connecticut,  Connecticut  State  Geol.   and  Nat.  Hist.  Survey  Bull.   6, 

pp.  223-259,  1906. 
Hager,  K.  D.  (1861).   See  Hitchcock,  Edward,  and  others  (1861). 
Hann,  Julius  (1911).     Klima  der  gemassigten  Zonen  und  der  Polar- 

zonen,  in  Handbuch  der  Khmatologie,  Vol.  3,  Part  2.  Stuttgart,  191 1. 
Hitchcock,  C.  H.  (1861).  See  Hitchcock,  Edward,  and  others  (1861). 
Hitchcock,  C.  H,  (1878).   Atlas  accompanying  the  report  on  the  geology 

of  New  Hampshire.    New  York,  1878. 
Hitchcock,  Edward  (1841).    Final  report  on  the  geology  of  Massachu- 
setts, Vol.  2,  pp.  350-422.     Amherst,  1841. 
Hitchcock,  Edward;  Hitchcock,  Edward,  Jr.;  Hagep.  A.  D.;  and 

Hitchcock,  C.  H.  (1861).   Report  on  the  geology  of  Vermont,  descrip- 
tive, theoretical,  economical,  and  scenographical.    2  vols.,  Claremont, 

N.  H.,  1861. 
Hitchcock,  Edw^ard,  Jr.  (1861).    See  Hitchcock,  Edward,  and  others 

(1861). 
HoBBS,  W.  H.  (1911).    Characteristics  of  existing  glaciers.    New  York. 

1911. 
HoBBS,  W.  H.  (1911a).     The    Pleistocene  glaciation  of  North  America 

viewed  in  the  light  of  our  knowledge  of  existing  continental  glaciers. 

Bull.  Amer.  Geogr.  Soc,  Vol.  43,  1911,  pp.  641-659. 


LIST  OF  REFERENCES  iii 

HOBBS,  W.  H.  (1915).  The  role  of  the  glacial  anticyclone  in  the  air  cir- 
culation of  the  globe.  Proc.  Amer.  Philos.  Soc,  Vol.  54.  1915.  PP-  185- 
225.    Philadelphia. 

Huntington,  Ellsworth  (1914).  The  climatic  factor  as  illustrated  in 
arid  America.    Carnegie  Instn.  Publ.  192.    Washington,  D.  C,  1914. 

Katz,  F.  J.,  AND  Keith,  A.  (191 7).  The  Newington  moraine,  Maine, 
New  Hampshire,  and  Massachusetts.  U.  S.  Geol.  Survey  Professional 
Paper  io8b,  191 7. 

Keith,  A.  (1917).   See  Katz,  F.  J.  (1917). 

Kemp,  J.  F.,  and  Ruedemann,  Rudolf  (1910).  Geology  of  the  Elizabeth- 
town  and  Port  Henry  quadrangles.  New  York  State  Museum  Bull. 
No.  138,  1910. 

Kindle,  E.  M.  (1913a).   See  Taylor,  F.  B.  (1913a). 

Knapp,  G.  N.  (1902).   See  Salisbury,  R.  D.,  and  others  (1902). 

KuMMEL,  H.  B.  (1902,  1902a,  1915).  See  Salisbury,  R.  D.,  and  others 
(1902  and  1902a)  and  Lewis,  J.  V.  (1915). 

Leverett,  Frank,  and  Taylor,  F.  B.  (1915) .  The  Pleistocene  of  Indiana 
and  Michigan  and  the  history  of  the  Great  Lakes.  U.  S.  Geol.  Survey 
Monograph  53,  1915- 

Lewis,  H.  C.  (1884).  Report  on  the  terminal  moraine  in  Pennsylvania 
and  western  New  York.  2nd  Geol.  Survey  of  Pennsylvania,  Kept,  of 
Progress  Z,  1884. 

Lewis,  J.  V.,  and  Kummel,  H.  B.  (1915).  The  geology  of  New  Jersey. 
Geol.  Survey  of  New  Jersey  Bull.  14,  191 5. 

Liden,  Ragnar  (1911).  Om  isafsmaltningen  och  den  postglaciala  land- 
hojningen  i  Angermanland.  Geol.  Foren.  Forhandl.,  Vol.  33,  1911, 
pp.  271-280.    Stockholm. 

Liden,  Ragnar  (19 13).  Geokronologiska  studier  ofver  det  finiglaciala 
skedet  i  Angermanland.  Sveriges  Geol.  Undersokning,  Ser.  Ca,  No.  9, 
19 13.    Stockholm. 

LouGHLiN,  G.  F.  (1905).  The  clays  and  clay  industry  of  Connecticut. 
Connecticut  State  Geol.  and  Nat.  Hist.  Survey  Bull.  4,  1905. 

Mather,  W.  W.  (1843).  Geology  of  the  First  Geological  District, 
in  Geology  of  New  York,  Part  i,  pp.  158-228.   Albany,  1843. 

Miller,  W.  J.  (1909).  Geology  of  the  Remsen  quadrangle.  New  York 
State  Museum  Bull.  No.  126,  1909. 

Miller,  W.  J.  (1910).  Geology  of  the  Port  Leyden  quadrangle,  Lewis 
County,  N.  Y.   New  York  State  Musemn  Bull.  No.  135,  191  o. 

Miller,  W.  J.  (1914).  Geology  of  the  North  Creek  quadrangle,  Warren 
County,  New  York.    New  York  State  Museum  Bull.  No.  170,  1914. 

Miller,  W.  J.  (1916).  Geology  of  the  Lake  Pleasant  quadrangle,  Hamil- 
ton County,  New  York.   New  York  State  Museum  Bull.  No.  182,  1916. 

Miller,  W.  J.  (1916a).  Geology  of  the  Blue  Mountain,  New  York,  quad- 
rangle.  New  York  State  Museum  Bull.  No.  192,  1916. 


112  ICE  RECESSION  IN  NEW  ENGLAND 

Oden,  Sven  (1918).    Automatisch  registrierbare  Methode  zur  mechan- 

ischen  Bodenanalyse.  Bull.  Geol.  Inst.  Upsala,  Vol,  16,  pp.  15-64,  1918. 
Oden,    Sven  (1919).     Uber  die  Vorbehandlung   der  Bodenproben  zur 

mechanischen  Analyse.    Bull.  Geol.  Inst.  Upsala,  Vol.  16,  pp.  125-134, 

1919. 
Oden,  Sven,  and  Reuterskiold,  A.  (1919a).    Zur  Kenntnis  des  An- 

cylustons.    Bull.  Geol.  Inst.  Upsala,  Vol.  16,  pp.  135-158,  1919. 
Oden,    Sven    (1920).     Die   automatisch   registrierende   Apparatur  zur 

mechanischen    Bodenanalyse    und    einige    damit    ausgefiihrte    agro- 

geologische  Untersuchungen.    Internatl.  Mitt,  fiir  Bodenkunde,  1920, 

pp.  301-342,    Berlin. 
Ogilvie,    I.   H.    (1902).     Glacial   phenomena  in  the  Adirondacks  and 

Champlain  valley.   Journ.  of  Geol.,  Vol.  10,  1902,  pp.  397—412. 
Peet,  C.  E.  (1902,  1902a).    See  Salisbury,  R.  D.,  and  others,  (1902, 

1902a). 
Peet,  C.  E.  (1904).    Glacial  and  post-glacial  history  of  the  Hudson  and 

Champlain  valleys.    Journ.  of  Geol.,  Vol.  12,  1904,  pp.  415-469  and 

617-661, 
von  Post,   Lennart   (191  i).    En  exakt  geologisk  tiderakning.    Pop.- 

Naturvet.  Revy,  1911,  pp.  11-20.    Stockholm. 
VON  Post,  Lennart  (1916).   Om  skogstradpoUen  i  syd  svenska  torvmos- 

sefoljder.    Geol.  Foren.  Forhandl.,  Vol.  38,  1916,  pp.  384-394.    Stock- 
holm. 
Reuterskiold,  A.  (1919a).    See  Oden,  Sven  (1919a). 
Rich,  J.  L.  (1906).    Local  glaciation  in  the  Catskill  Mountains.    Journ. 

of  Geol.,  Vol.  14,  1906,  pp.  113-121. 
Rich,  J.  L.  (1914).    Divergent  ice-flow  on  the  plateau  northeast  of  the 

Catskill   Mountains  as  revealed   by  ice-molded   topography.     Bull. 

Geol.  Soc.  of  America,  Vol.  25,  1914,  pp.  68-70. 
Rich,  J.  L.  (191 5).    Notes  on  the  physiography  and  glacial  geology  of 

the  northern  Catskill  Mountains.  Amer.  Journ.  of  Sci.,  Ser.  4,  Vol.  39, 

1915.  PP-  137-166. 
Ruedemann,    Rudolf    (1910,    1910a).     See  Kemp,   J.  F.  (1910),    and 

Gushing,  H.  P.  (1910). 
Salisbury,  R.  D.,  Kummel,  H.  B.,  Peet,  C.  E.,  and  Knapp,  G.  N. 

(1902).   The  glacial  geology  of  New  Jersey.  Final  Report  of  the  Geol- 
ogical Survey  of  New  Jersey,  Vol.  5,  1902. 
Salisbury,  R.  D.,  Kummel,  H.  B.,  and  Peet,  C.  E.    (1902a).    New 

York  City  Folio.     U.  S.  Geol.  Survey  Geologic  Atlas,  Folio  No.  83,  1902. 
Salisbury,  R.  D.  (1908).  Quaternary  System,  Passaic  Folio,  N.  J.-N.  Y., 

U.  S.  Geol.  Survey  Geologic  Atlas,  Folio  No.  157,  1908,  p.  14. 
Sandegren,    R.    (191 5).     Ragundatraktens    postglaciala    utvecklings- 

historia    enligt    den    subfossila    florans    vittnesbord.     Sveriges    Geol. 

Undersokning,  Ser.  Ca,  No.  12,  1915.    Stockholm. 


LIST  OF  REFERENCES  113 

Sauramo,  Matti  (1918).  Geochronologische  Studien  iiber  die  spat- 
glaziale  Zeit  in  Siidfinnland.  Bull.  Comin.  Geol.  de  -Finlande  No.  50, 
1918;  also  Fennia,  Vol.  41,  No.  i,  pp.  1-44,  Helsingfors,  1918. 

Sayles,  R.  W.  (1919).  Seasonal  deposition  in  aqueo-glacial  sediments. 
Memoirs  Museum  of  Comp.  Zool.,  Vol.  47,  No.  i.  Cambridge,  Mass., 
1919. 

Sayles,  R.  W.  (1922).  The  dilemma  of  the  paleoclimatologists.  Amer. 
Journ.  of  Sci.,  Ser.  5,  Vol.  3,  1922,  pp.  456-473. 

Shaler,  N.  S.  (1889).  The  conditions  of  erosion  beneath  deep  glaciers, 
based  upon  a  study  of  the  boulder  train  from  Iron  Hill,  Cumberland, 
R.  I.  Bull.  Museum  of  Com,p.  Zool.,  Vol.  16,  1889,  pp.  185-225.  Cam- 
bridge, Mass. 

Smith,  Alfred  (1832).  On  the  water  courses  and  the  alluvial  and  rock 
formations  of  the  Connecticut  River  valley.  Amer.  Journ.  of  Sci.  and 
Arts,  Vol.  22,  1832,  pp.  205-231. 

Smyth,  C.  H.,  Jr.  (1910).   See  Cushing,  H.  P.,  and  others  (1910). 

Stoller,  J.  H.  (191 1).  Glacial  geology  of  the  Schenectady  quadrangle. 
New  York  State  Museum  Bull.  No.  154,  191 1. 

Stoller,  J.  H.  (1916).  Glacial  geology  of  the  Saratoga  quadrangle. 
New  York  State  Museum  Bull.  No.  183,  1916. 

Tarr,  R.  S.  (1903).  Post-glacial  and  inter-glacial  changes  of  level  at 
Cape  Ann,  Mass.,  with  a  note  on  the  elevated  beaches  hy  }.  B.  Wood- 
worth.  Bull.  Miiseum  of  Comp.  Zool.,  Vol.  42,  1903,  pp.  181-196. 
Cambridge,  Mass. 

Tarr,  R.  S.  (1909).  Watkins  Glen-Catatonk  Folio.  U.  S.  Geol.  Survey 
Geologic  Atlas,  Folio  No.  i6q,  1909. 

Taylor,  F.  B.  (1894).  The  limit  of  postglacial  submergence  in  the  high- 
lands east  of  Georgian  Bay.    Amer.  Geologist,  Vol.  14, 1894,  pp.  273-289.' 

Taylor,  F.  B.  (1903).  The  correlation  and  reconstruction  of  recessional 
ice  borders  in  Berkshire  County,  Mass.  Journ.  of  Geol.,  Vol.  11,  1903, 
pp. 323-364. 

Taylor,  F.  B.  (1913).  The  glacial  and  postglacial  lakes  of  the  Great 
Lakes  region.    Ann.  Rept.  Smithsonian  Instn.for  1912,  pp.  291—327. 

Taylor,  F.  B.,  and  Kindle,  E.  M.  (1913a).  Niagara  Folio.  U.  S.  Geol. 
Survey  Geologic  Atlas,  Folio  No.  190,  1913. 

Taylor,  F.  B,  (1915).  See  Leverett,  Frank,  and  Taylor,  F.  B.  (1915). 

Upham,  Warren  (1878).  Modified  drift,  in  C.  H.  Hitchcock:  Geology'' 
of  New  Hampshire.    Concord,  N.  H.,  1878. 

Upham,  Warren  (1888).  The  geology  of  Carver  and  Scott  Counties, 
in  The  Geology  of  Minnesota,  Final  Report,  Vol.  2,  pp.  102-147, 
Geol.  and  Nat.  Hist.  Survey  of  Minn.    1888. 

Ward,  Freeman  (1920).  The  Quaternary  geology  of  the  New  Haven 
region,  Connecticut.  Connecticut  State  Geol.  and  Nat.  Hist.  Survey 
Bull.  29,  1920. 


114  ICE  RECESSION  IN  NEW  ENGLAND 

WooDWORTH,  J.  B.  (1896).   The  retreat  of  the  ice-sheet  in  the  Narragan- 

sett  Bay  region.    Amer.  Geologist,  Vol.  18,  1896,  pp.  150-168. 
WooDVVORTH,  J.  B.  (1897).    Some  glacial  wash-plains  of  southern  New 

England.    Bull.  Essex  Inst.,  Vol.  29,  1897.    Salem,  Mass. 
WooDWORTK,  J.  B.  (1901).    Pleistocene  geology  of  portions  of  Nassau 

County  and  Borough  of  Queens,  New  York  State  Museum  Bull.  No. 

48,  1901. 
WooDWORTH,  J.  B.  (1903).    See  Tarr,  R.  S.  (1903), 
WooDWORTH,  J.  B.  (1905).    Pleistocene  geology  of  Mooers  quadrangle. 

New  York  State  Museum  Bull.  No.  83,  1905. 
WooDWORTH,  J.  B.  (1905a).   Ancient  water  levels  of  the  Champlain  and 

Hudson  valleys.  New  York  State  Museum,  Bull.  No.  84,  1905. 


INDEX 


INDEX 


Adirondack  Mountains,  95,  100,  103, 
104 

Agassiz,  Louis,  vii 

Albany,  N.  Y.,  46,  99 

Albany,  glacial  Lake,  99 

Alden,  Mr.,  104 

Alden  moraine,  97 

American  Geographical  Society,  xii, 
xiii;  photostat  copies  of  the  normal 
curve,  48 

Amherst,  Mass.,  53,  66,  93;  clay  pits,  18; 
section  showing  till  and  partially 
folded  clay  (diagr.),  77 

Amherst-Northampton  region,  oscilla- 
tions of  ice  border,  77 

Ann,  Cape,  106 

Arkona,  glacial  Lake,  97 

Arthur  Kill,  7 

Ascutneyville,  Vt.,  bluff,  28 

Ashuelot  River,  19 


Baltic  region,  8,  85,  86 

Bear  Island,  85 

Bellows  Falls,  Vt.,  lake,  82;  localities 
studied  near,  20,  21,  22 

Berkshires,  92,  94,  96,  107 

Bethlehem,  N.  H.,  83,  95 

Bibliography,  108 

Blackmount  station,  N.  H.,  31 

Blekinge,  90 

Boscawen,  N.  H.,  railroad  cut,  27 

Boston,  9,  94 

Bottom  varves,  loi 

Boulder  dispersion,  Sources  of  informa- 
tion, 104 

Bow  Junction,  N.  H.,  23 

Boyce  station,  N.  H.,  25 

Bradford,  Vt.,  bluff,  30 

Brattleboro,  Vt.,  brickyard,  19 

Bruckner,  Eduard,  88,  93 

Buffalo,  N.  Y.,  97 


Calving,  86,  87 

Canterbury  station,  N.  H.,  clay  pit,  27 

Catskill,  N.  Y.,  46;  drainage  curve,  98 

(diagr.),  99 
Catskill  Mountains,  95,  97,  103, 104, 107 
Chamberlin,  T.  C,  95 


Champlain,  Lake,  100 

Charlestown,  N.  H.,  river  bluffs,  21,  22 

Charter    Oak     Park,    near    Hartford, 

Conn.,  II 
Chicopee,  Mass.,  brickyard   clay  pits, 

13.  14 
Chronology,  normal  curve  and  absolute 

time,  48 
Claremont,  N.  H.,  47,  74,  79,  81,  93,  95, 

100;  localities  studied  near,  22,  28 
Claremont  Junction,  N.  H.,  clay  pit,  23 
Clay,  disturbances  in,  72;  type  of  clay 

and  late  of  retreat,  84.     See  also 

Varves 
Clay  Brook,  N.  H.,  bluff,  30 
Clay  Point,  near  Wolfeboro,  N.  H.,  81 
Climate,  during  recession,  89;  Sweden 

and  New  England,  90 
Climatic  periodicity,  91 
Coeymans,  N.  Y.,  46 
Cohoes,  N.  Y.,  46,  95.  99 
Concord,  N.  H.,  95;  abnormal  varves, 

69;  lake,  82;  localities  studied  near, 

23,  24,  25,  26,  27 
Conicut  station,  Vt.,  ravine,  31 
Connecticut      River,      junction     with 

Passumpsic  River,  34,  35,  61,  66; 

oxbow,  17 
Connecticut  Valley,  correspondences  of 

varve   curves   with   Merrimac   and 

Hudson      Valleys,      67;      localities 

studied,     11,     28;     maps     showing 

localities  studied,  37-44 
Connections,  64 
Correspondences,  67 
Coxsackie,  N.  Y.,  46 
Crowfoot  Brook,  14 
Curves.     See    Normal    curve,    Varve 

curves 
Cycles,  climatic,  92 


De  Geer,  Gerard,  viii,  3,  84,  loi ;  Hudson 
Valley  ice  recession,  46;  New  Eng- 
land and  Sweden  ice  retreat,  48; 
temperature  studies,  85;  time  scale, 
xi,  4;  Wells  River,  Vt.,  and 
Woodsville,  N.  H.,  32 

Disturbances  in  the  clay,  72 

Douglass,  A.  E.,  92 


ii8 


ICE  RECESSION  IN  NEW  ENGLAND 


Drainage  varves,  69 

Drainages,  70;  three  drainages  into  the 
Connecticut  River  above  its  junc- 
tion with  the  Passumpsic,  70,  71 

East  Putney,  Vt.,  railroad  cut,  20 

East  Ryegate,  Vt.,  ravine  and  bluffs,  34 

East  Windsor  Hill,  Conn.,  13 

Easthampton,  Mass.,  16 

Emerson,  B.  K.,  3,  9,  37.  Si.  80,  89.  95 

Erie,  Lake,  basin,  97,  100 


Fairchild,  H.  L.,  9 

Fauna,  89 

Fenno-Scandia,  9.  49,  84,  87,  90,  93 

Finger  Lakes  district,  95,  97.  99 

Finland,  79,  86,  87;  rate  of  ice  retreat, 

92  (diagr.),  93 
Fisher's  Island,  8 
Flora,   103;  Northampton  varve  clay, 

89;  Sweden,  90 
Forest  Park,  near  Springfield,  Mass.,  13 
Fort  Hill  station,  N.  H.,  railroad  cut,  19 
Franklin,  N.  H.,  clay  pit,  27 


Genesee  River,  97 

Glacial  lakes.   See  Lakes 

Glacial  rivers,  i,  9 

Glacial  theory,  vii 

Glaciers,  local,  103 

Glens  Falls,  107 

Goldthwait,    J.  W.,  xii,  9.  81,  84,  95, 

loi;  explanation  of  map   (PI.  VI), 

104;  map  of  ice  retreat,  94;  Preface, 

vii 
Great  Lakes  region,  correlation  of  ice 

retreat  with  that  of  New  England, 

95;  first  escape  of  waters,  98,  99; 

moraines,  107 
Greenfield,  Mass.,  brickyards,  18;  part 

of  curves  (diagr.),  102;  reliability  of 

varves,  54 
Grout   station,    Vt.,    localities   studied 

near,  20 


Hackensack,  N.  J.,  7.  8 

Hadley,  Mass.,  17 

Hampshire  Brick  Co.,  IS 

Hanover,  N.  H.,  83;  localities  studied 

near,  29,  30;  thick  drainage  varve, 

70 
Hartford,  Conn.,  brickyards,  11,  12,  13; 

reliability     of    varves,     49;     varve 

number,  49 


Haverhill  station,  N.  H.,  ravines 
studied  near,  30,  31 

Hinsdale,  N.  H.,  55 

Hitchcock,  C.  H.,  9,  37,  45 

Hitchcock,  Edward,  vii,  3 

Hobbs,  W.  H.,  86 

Holyoke,  Mass.,  brickyards,  14,  15 

Holyoke  Brick  Co.,  14 

Holyoke  Range,  52,  66 

Hookset,  N.  H.,  23 

Hudson,  N.  Y.,  46,  96 

Hudson  River,  elevation  of  lower 
district,  9 

Hudson  Valley,  55,  83,  99,  106;  cor- 
respondences with  Connecticut  and 
Merrimac  Vallej^s,  67;  localities 
used,  46 

Huron,  Lake,  basin,  99 


Ice  border,  oscillations,  77,  81;  rate  of 
retreat,  75 

Ice  flow,  direction,  sources  of  informa- 
tion, 104 

Inwood,  Vt.,  93;  localities  studied,  35, 
36 

Iroquois,  Lake,  100 

Isobases,  106 


Jackson,  C.  T.,  vii 
Jeffrey.  E.  C,  90 


Keene,  N.  H.,  brickyard,  19 
Kingston,  N.  Y.,  97 


Lake  sediments,  9 

Lakes,  formation  of  ice  front,  9;  glacial 

lakes  outlines  ^n   Connecticut  and 

Merrimac   Valleys    (maps),    37-45; 

problems,    loi;    White    Mountains, 

71,  72 
Late  glacial  time,  definition,xi 
Leverett,  Frank,  96,  107 
Liden,  Ragnar,  viii,  xi;  Wells  River  and 

Woodsville  samples,  32 
Little  Sugar  River,  bluff,  22 
Littleton,  N.  H.,  83 
Localities  studied,  11 
Long  Island,  8 
Long  Island  Sound,  8 
Loughlin,  G.  L.,  9,  37 
Lundy,  Lake,  100 
Lynch  Brickyard,  14 


INDEX 


119 


Map  illustrating  the  recession,  opp.  120; 
explanation,  104 

Marine  clays,  3 

Mascoma  River,  29,  58 

Mather,  W.  W..  vii 

Mathews,  E.  B.,  xii 

Measuring  clay  layers  (ill.),  opp.  5 

Merrimac  Valley,  82;  correspondences 
of  varve  curves  with  Connecticut 
and  Hudson  Valleys,  67;  localities 
studied,  23;  map  of  localities 
studied,  45;  reliability  of  varves,  56 

Middletown,  Conn.,  52 

Mink  Brook,  N.  H.,  29 

Mohawk  River,  46 

Mohawk  Valley,  83,  95.  99.  100 

Montague  City,  Mass.,  brickyards,  18, 
19 

Moraines,  Berkshires,  92;  Great  Lakes 
region,  96;  sources  of  information, 
105 


Narrows,  the,  7 

National  Research  Council,  xii 

Nevel's  Brickyard,  12 

New  England,  abundance  and  quality 
of  material,  65;  conditions  during 
deposition  of  the  varve  clay,  7; 
southern,  higher  elevation  in  late 
glacial  time,  7 

New  Haven,  Conn.,  7,  8 

New  York  (city),  7 

New  York  (state),  9Si  96 

Newbury,  Vt.,  clay  pits,  31 

Newington  moraine,  106 

Niagara  Falls,  97,  99 

Normal  curve,  opp.  120;  absolute  time 
and,  48;  method  of  construction,  47; 
symbols  explained,  48 

North  Charlestown,  N.  H.,  22 

Northampton,  Mass.,  66,  95;  brick- 
yards, 16,  17;  flora  in  varve  clay,  89; 
part  of  curves  (diagr.)  78;  reliability 
of  varves,  53.  See  also  Amherst- 
Northampton  region 

Northboro  station,  N.  H.,  clay  pit,  30 

Northeastern  States,  previous  knowl- 
edge of  ice  retreat,  94 


Oden,  Sven,  103 
Ontario,  Lake,  100 
Ontario,  Lake,  basin,  95 


Oscillations  of  ice  border,  Amherst- 
Northampton  region,  77;  Lake 
Winnepesaukee  region,  81 

Oxbow  of  Connecticut  River,  17 


Park  Brickyard,  11 

Passumpsic,  Vt.,  slide,  36 

Passumpsic  River,  junction  with  Con- 
necticut River,  34,  35,  61,  66 

Passumpsic  Valley,  66,  83 

Pecowsic  Brook,  13 

Peet,  C.  E.,  107 

Pembroke,  N.  H.,  23 

Penacook  station,  N.  H.,  26 

Periodicity,  climatic,  91 

Peripheral  land,  rising  of,  8 

Plants,  pollen  in  clays,  103.  See  also 
Flora 

Podunk  River,  12 

Port  Huron  morainic  system,  97 

Post,  Lennart  von,  103 

Post-glacial  time,  definition,  xi 

Precipitation,  85,  86,  87 

Previous  knowledge  of  ice  retreat,  94 

Problems  to  be  studied,  100 

Putney,  Vt.,  brickyard,  19 


Ragunda,  xi,  90;  flora  and  climate,  103 

Rainfall,  85,  86,  87 

Rate  of  recession,  74,  90 

Recession,  conditions  controlling,  85; 
previous  knowledge,  94;  rate,  74,  90; 
rate  in  middle  zone,  81;  rate  in 
northern  zone,  83;  rate  in  southern 
zone,  76;  rate  of  retreat  and  tj^pe  of 
clay,  84 

References,  108 

Rich,  J.  L.,  95,  104,  107 

Rome,  N.  Y.,  100 


St.  Johnsbury,  Vt.,  83,  100;  slide  near, 

36 
St.  Lawrence  Valley,  100 
Salpausselka,  87,  93 
Sandegren,  R.,  103 
Sauramo,  Matti,  79.  88,  92,  93 
Sayles,  R.  W.,  xii,  xiii,  90 
Schenectady,  N.  Y.,  99 
Sedimentation  problems,  loi,  103 
Sediments,  9 
Simon  Lake,  Quebec,  varve  clay  (ill.), 

opp.  4 


120 


ICE  RECESSION  IN  NEW  ENGLAND 


Smith.  Alfred,  3 

South  Hadley,  Mass.,  15 

South  Hadley  Falls,  Mass.,  14 

South  Windsor,  Conn.,  12 

Spitsbergen,  85 

Springfield,     Mass.,     brickyards,      13; 

reliability  of  varves,  49 
Stockholm,  loi 
Stockport,  N.  Y.,  46 
Stony  Brook,  South  Hadley,  Mass.,  15 
Stoughton's  Brook,  13 
Striae,  sources  of  information,  104 
Sugar  Ball  Bluff,  N.  H.,  25 
Sugar  River,  28 
Suncook,  N.  H.,  23 
Suncook  River,  late  glacial,  57 
Superior,  Lake,  87 
Sverige  Amerika  Stiftelsen,  xii 
Sweden,  flora,  90;  ice   retreat,   xi;   ice 

retreat    as    compared    with     New 

England,  48;  rate  of  ice  retreat,  90; 

temperature,  85,  86 
Syracuse,  N.  Y.,  97,  99 


Tarr,  R.  S.,  106 

Taylor,  F.  B.,  3,  92,  95,  96,  107 
Temperature,  85,  89.    See  also  Climate 
Topography,     influence     on     rate     of 

recession,  87 
Turners  Falls,  Mass.,  brickyard,  19 


Upham,  Warren,  3,  81,  82,  95 
Utica,  N.  Y.,  97 


Varve  clay,   formation,    i;   manner  of 

deposition     (ill.),     2;     method     of 

investigation,  3 
Varve  curves,  agreement  from  widely 

separated    localities,    67;    examples 

illustrating  agreement,  65 


Varve  studies,  bearing  on  previous 
work,  94;  confirmations,  95;  contri- 
bution to  the  problem  of  glacial 
correlation  of  Great  Lakes  region 
and  New  England,  96;  future 
problems,  100 

Varves,  abnormal,  69;  abnormally 
thick,  69;  bottom,  10 1;  connections, 
64;  definition,  xi,  3;  drainage  varves, 
69;  exposure  of  varve  clay  (ill.), 
opp.  4;  measuring,  4,  opp.  s  (ill.); 
New  England,  character,  65;  relia- 
bility of  those  measured,  discussion 
by  groups,  49;  thickness,  meaning 
of,  72;  value  for  study,  64 


Walker  Brook,  28 

Warren,  Lake,  97,  99 

Wayne,  Lake,  98,  99 

Weirs,  N.  H..  81 

Wells  River,  Vt.,  De  Geer's  locality,  32; 

localities  studied  near,  31 
Westboro,    N.    H.,    localities    studied 

near,  29 
Westfield,  Mass.,  brickyard  clay  pits, 

15,  16 
Westminster    station,    Vt.,    slide    and 

bluff  near,  21 
White  Mountains,  95,  103;  ice-ponded 

lakes,  71,  72 
White  River,  58,  68,  83 
White  River  Junction,  Vt.,  ravine,  29 
Whittlesey,  Lake,  97,  99 
Willimansett,  Mass.,  14 
Wilson,  Conn.,  12 
Windsor,  Vt.,  bluff  near,  28 
Winnepesaukee,  Lake,  95,  100;  oscilla- 
tions   of    the    ice    border    in    the 

region,  81 
Wolfeboro,  N.  H.,  81 
Woodsville,  N.  H.,   10,  84;  De  Geer's 

locality,  32;  localities  studied  near. 

30,    31,    32,    33,    34;    reliability    of 

varves,  59,  60 
Woodworth,  J.  B.,  9.  104 


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